Building a beginner PC starts with choosing compatible core parts: a CPU, motherboard (matching the CPU socket), RAM, storage (SSD recommended), power supply (PSU), case, and either integrated graphics or a dedicated GPU. First install the CPU, cooler, and RAM onto the motherboard, then mount the motherboard in the case, add the PSU, storage, and GPU, and connect all power/front-panel cables carefully. After assembly, connect a monitor, boot into BIOS to confirm parts are detected, then install your operating system. Using tools like PCPartPicker for compatibility checks, following motherboard manuals, and watching step-by-step build videos can make the process much easier and help avoid common mistakes like incorrect cable placement or insufficient power supply sizing.