How to Build a PC Step by Step: A Complete Guide for Beginners (2026)

31 July 2026

Building a PC from scratch can seem daunting if you've never done it before. Cables everywhere, slots you're not sure where to put, screws left over at the end... However, the reality is that anyone with a little patience and the right instructions can do it. And the benefits are huge: you save money, you get exactly the performance you need, and you get to know your machine inside out.

In this complete guide, we explain how to build a PC step by step, from choosing the components to turning it on for the first time. Whether you want to build a gaming PC that can run the latest games or you're looking for a powerful rig for work or study, here's everything you need to know.

What you need: list of components for building a PC

Before we start, let’s go over what parts you’ll need. These are the essential components for building a PC:

Processor (CPU) — The brain of the computer. It can be Intel or AMD.
Motherboard — This connects and allows all components to communicate with each other.
RAM — The system’s working memory. The more you have, the better your multitasking.
SSD — Where you install the operating system and programs. Much faster than a traditional HDD.
Graphics card (GPU) — Essential for gaming, 3D design or video editing.
Power supply unit (PSU) — Supplies power to all components.
Case or tower — The casing that houses everything.
Cooling — A heatsink for the CPU (may come included, or you can buy a better one).

In addition to the components, you’ll need:

A medium-sized Phillips head screwdriver
Thermal paste (if the heatsink doesn’t include it)
An anti-static wrist strap or anti-static surface (recommended)
Cable ties or Velcro for cable management (optional but very useful)

Step 1: Choose the right components

Why is compatibility so important?

Not all components work together. The processor must be compatible with the motherboard (same socket), the RAM must be of the type the motherboard supports (DDR4 or DDR5), and the power supply must have enough wattage to power the entire system. Spending time on this step will save you a lot of headaches.

Processor (CPU): Intel or AMD

In 2026, both Intel and AMD offer excellent processors for every budget. For a first mid-range gaming PC, an option like the AMD Ryzen 5 or Intel Core i5 is more than enough. If you want more power for streaming, video editing or professional work, step up to the Ryzen 7 / Core i7 range.

View AMD and Intel processors at Probyte →

? Related: Best processors for gaming

Motherboard: the backbone of your PC

The motherboard must be compatible with your processor. Pay attention to the socket (AM5 for current Ryzens, LGA1851 for Intel) and the chipset, which determines available features: overclocking, number of USB ports, M.2 slots for SSDs, etc.

For a standard build, a mid-range motherboard offers everything you need without overpaying: B650 or B850 chipsets for AMD (AM5 socket) and B860 for Intel on the current LGA1851 socket. If you choose a 12th to 14th Gen Intel (LGA1700 socket, still widely sold for price), its mid-range chipset is the B760 — never mix an LGA1700 board with an LGA1851 processor or vice versa.

View motherboards at Probyte →

RAM: speed and capacity

16 GB of RAM is the minimum recommended for gaming and general use in 2026. If you're into video editing, 3D design or using virtual machines, consider 32 GB. Ensure the RAM speed (expressed in MHz) is compatible with your motherboard.

View RAM at Probyte →

? Related: 16, 32 or 64 GB? How much RAM you really need · How RAM affects your FPS

SSD: storage speed

Forget mechanical hard drives for the operating system. An NVMe M.2 SSD is between 5 and 10 times faster than an HDD and will make your PC boot in seconds. For the OS and main programs, 500 GB or 1 TB is more than enough. You can add another SSD or an HDD for additional storage later.

View SSDs at Probyte →

Graphics card: the heart of the gaming PC

If your goal is gaming, the graphics card (GPU) will likely be the most important (and most expensive) component. For 1080p at high quality, a mid-range GPU is more than enough. For 1440p or 4K, you'll need a high-end card. NVIDIA and AMD are the two main manufacturers; both offer excellent options.

View graphics cards at Probyte →

? Related: Best budget graphics cards

Power supply: don't skimp here

The power supply is one component where you should skimp the least. A poor quality PSU can damage the rest of the system. Choose one with at least 80 Plus Bronze certification (Gold or Platinum is better) and enough wattage for your components. As a general rule, if you have a high-end GPU, you'll need between 650 W and 850 W.

View power supplies at Probyte →

Case: space and airflow

The case determines what size motherboard you can use (ATX, Micro-ATX, Mini-ITX) and how many fans fit. For a first PC, a mid-tower ATX case is the most comfortable option: enough space to work in, good airflow, and compatibility with most components on the market.

View cases at Probyte →

? Related: How to choose a case for your gaming PC

Cooling: keep your CPU cool

Many processors include a heatsink in the box (the so-called stock cooler). It's functional, but if you want less noise or lower temperatures, it's worth investing in an aftermarket cooler or, if you're up for it, liquid cooling.

View cooling systems at Probyte →

? Related: Which liquid cooling to choose?

Paso 2: Prepara el espacio de trabajo

Busca una mesa amplia, bien iluminada y libre de alfombras o superficies que generen electricidad estática. Retira las bolsas de plástico cuando no las necesites. Antes de tocar cualquier componente, toca una superficie metálica (como el chasis de la caja) para descargarte de electricidad estática.

Ten a mano todas las cajas de los componentes con sus manuales: la placa base en especial incluye instrucciones muy claras sobre cómo instalar cada pieza.

Step 3: Assemble the motherboard outside the case (first review)

A good trick for beginners is to do a trial installation outside the case before assembling everything. This way, you can check that the components work before screwing everything together.

Install the processor on the motherboard

Remove the motherboard from its box and place it on its anti-static packaging on the table.
Open the CPU socket (there is a lever or a pressure mechanism depending on the manufacturer).
Align the processor with the notch or arrow that indicates the correct orientation.
Place the CPU gently, without forcing it. Never push with force.
Close the socket's locking mechanism.

Install the RAM

Open the tabs on the RAM slots.
Consult the motherboard manual to know which slots to install the modules in (usually slots 2 and 4 to take advantage of dual channel mode).
Align the notch on the module with the slot and press firmly until the tabs click.

View RAM memories on Probyte →

Install the M.2 SSD (if applicable)

If your SSD is in the M.2 format, it's time to install it in the M.2 slot on the motherboard before putting it in the case. Insert the SSD at an angle, press down, and secure it with the corresponding screw.

View M.2 SSDs on Probyte →

Paso 4: Prepara la caja

Retira los paneles laterales de la caja.
Instala los separadores de latón (standoffs) en los orificios correspondientes al tamaño de tu placa base (ATX, Micro-ATX...). Estos separadores elevan la placa base para que no haga contacto directo con el metal de la caja.
Instala el panel de I/O (el escudo de puertos traseros) que viene con la placa base. Encaja desde dentro hacia afuera en el hueco rectangular de la parte trasera de la caja.

Ver cajas y torres en Probyte →

Paso 5: Instala la placa base en la caja

Con los separadores y el panel de I/O ya colocados, mete la placa base en la caja alineándola con los orificios de los separadores y el panel trasero. Atornilla la placa base de forma cruzada (como si apretaras las ruedas de un coche) para distribuir la presión uniformemente. No aprietes demasiado.

Step 6: Install the power supply

The power supply is normally installed in the rear bottom of the case. Insert it with the fan facing downwards (if the case has a ventilation grid at the base) or upwards if it does not. Screw the four PSU screws from the rear of the case.

View power supplies at Probyte →

Step 7: Install the CPU cooler

Apply a small amount of thermal paste to the centre of the processor (about the size of a pea) if the cooler does not already have it applied.
Secure the cooler to the processor by following the manufacturer's instructions. Each model has a different fastening system.
Connect the cooler fan cable to the CPU_FAN connector on the motherboard.

View cooling systems at Probyte →

Step 8: Install the Graphics Card

Remove the covers from the rear expansion slots on the case that correspond to the position where the GPU will go.
Insert the graphics card into the PCIe x16 slot on the motherboard (usually the longest slot, closest to the processor). Press down until the retention clip clicks.
Screw the GPU into the case using the screws on the rear bracket.

View graphics cards at Probyte →

Paso 9: Conecta todos los cables

Este es el paso que más asusta a los principiantes, pero con el manual de la placa base delante es más sencillo de lo que parece. Los cables principales que tienes que conectar son:

Cable de 24 pines ATX → conector principal de alimentación de la placa base
Cable de 8 pines (o 4+4) → alimentación del procesador, en la esquina superior izquierda de la placa
Cable(s) PCIe de 6+2 pines → alimentación de la tarjeta gráfica (si la necesita)
Cables SATA → para discos SSD o HDD adicionales con interfaz SATA
Cables del panel frontal → Power button, Reset, LEDs de actividad HDD, USB frontales, audio frontal. El manual de la placa base indica exactamente dónde va cada pin.
Cables de ventiladores → conecta los ventiladores de la caja a los conectores SYS_FAN de la placa base

Consejo: Ve pasando los cables por detrás del chasis siempre que puedas. Mejora el flujo de aire y el aspecto visual del equipo.

Step 10: First boot and BIOS configuration

This is the moment of truth! Before closing the case, connect a monitor, keyboard and mouse, and press the power button.

What should happen?

The fans start spinning.
The monitor shows the BIOS screen or the motherboard manufacturer's logo.

Basic BIOS setup

Enter the BIOS by pressing the key indicated during boot (usually Delete, F2 or F12).
Check that the processor and RAM are detected correctly.
Enable the RAM's XMP/EXPO profile so it runs at its rated speed.
Set the boot order so that your USB drive with the operating system installer is the first device.
Save changes and restart.

Paso 11: Instala el sistema operativo

Con un USB preparado previamente con el instalador de Windows 11 (o la distribución Linux que prefieras), sigue los pasos en pantalla para instalar el sistema operativo. Una vez terminado, instala los drivers de la placa base, la tarjeta gráfica y demás componentes. La mayoría de los fabricantes los tienen disponibles en su página web.

Common mistakes when building a PC (and how to avoid them)

Forgetting to install the I/O panel before the motherboard. This is the most frequent error. Once the board is screwed in, you have to disassemble it to place it.
Not connecting the 8-pin CPU cable. The PC will not start if this cable is missing.
Applying too much thermal paste. It does not improve performance and can stain the processor's pins.
Installing RAM in the wrong slots. Consult the motherboard manual.
Not connecting the power cable to the GPU. The graphics card will not function without it.

How much does it cost to build a PC in 2026?

The cost depends entirely on your goals. As a rough guide:

Type of PC	Price range (components only)
Office and study PC	350 – 550 €
Entry/mid-range gaming PC	600 – 900 €
High-end gaming PC	1,000 – 1,800 €
Professional workstation PC	1,500 € and up

In all cases, building the PC yourself is significantly cheaper than buying a pre-built one, and you get exactly what you need.

FAQ: Frequently Asked Questions About Building a PC

Is it difficult to build a PC from scratch?

No. With the right instructions and a bit of patience, anyone can build their first PC in 2 to 4 hours. The components are designed to fit together in only one way, minimising the risk of mistakes. The biggest challenge is usually cable management.

What tools do I need to build a PC?

Basically, a Phillips-head screwdriver. It's also advisable to have thermal paste (if the cooler doesn't include it), an anti-static wrist strap, and cable ties for organising the cables. You don't need any special tools or advanced technical knowledge.

Can I build a gaming PC on a low budget?

Yes. With a budget between €600 and €900, you can build a gaming PC capable of running current games at 1080p with high quality. The key is choosing the right components and prioritising the processor and graphics card. At Probyte, you'll find options for all budgets.

What if the PC doesn't turn on the first time?

This is more common than you think and almost always has a simple solution. Check that all power cables are properly connected (especially the 24-pin ATX and the 8-pin CPU), that the RAM is correctly inserted, and that the front panel cable (Power SW) is on the correct pins on the motherboard.

Do I need to buy the operating system as well?

Windows 11 has an additional cost if you want an official licence. You can also install it in evaluation mode for free, or choose a completely free Linux distribution like Ubuntu, which is an excellent option for daily work and study.

Build your PC with the best components from Probyte

Now that you know how to build a PC step by step, all you need is the most important thing: the components. At Probyte, you'll find everything you need to build your ideal machine, with the best prices, fast shipping across Spain, and expert advice if you need it.

Do you have doubts about which components to choose? Visit www.probyte.com and our team will be happy to help you configure the perfect PC for you.

Article updated in July 2026 | Probyte — Your computer and technology store