How do you build a PC step by step?

Reviewed by Hritik, White Fortress Academy · last reviewed 2026-11-11

Check that the parts are compatible, install the CPU, memory and any M.2 drive on the motherboard, fit the cooler, mount the power supply and motherboard in the case, add the graphics card, connect the power and front-panel cables, then boot into the BIOS to confirm everything is detected.

Build order

  1. Check compatibility first: the CPU must fit the motherboard socket, the RAM type (for example DDR4 or DDR5) must match the board, and the power supply must give enough wattage.
  2. Fit the CPU, RAM and any M.2 drive on the motherboard while it is outside the case, where there is more room.
  3. Fit the CPU cooler, with thermal paste if it is not already applied.
  4. Mount the power supply, then the motherboard on its standoffs in the case.
  5. Add storage drives and the graphics card.
  6. Connect the power cables: the motherboard’s main connector, the CPU power, and the graphics card if it needs it.
  7. Connect the front-panel and fan cables.
  8. Check every connector, then boot into the BIOS and confirm the CPU, RAM and storage are detected before installing an operating system.

Handling parts safely

Work on a clean, hard surface, touch bare metal on the case to discharge static before you handle parts, and hold components by their edges.

Common mistakes

Questions people ask

Which part should I install first?

Most builders fit the CPU, RAM and any M.2 drive onto the motherboard before putting it in the case, because there is more room to work.

Why will my new PC not turn on?

Common causes are an unplugged CPU power cable, memory that is not fully seated, a loose front-panel power-switch cable, or a power supply switch that is off. Reseat the parts and check every power connector.

Practise it: Hardware Builder

Also in the arcade: Hardware Builder, a build-a-PC game for learning computer parts · OS Installation Challenge. Terms: cpu processor, ram, motherboard, psu power supply. All quick answers · IT glossary

Plain-English guide by White Fortress Academy.