Have you ever installed a new hard drive / RAM / CPU in a desktop computer?

These are standard PC hardware tasks. Power down and unplug the machine, and observe ESD precautions (wrist strap / touch a grounded chassis) since these parts are static-sensitive.

• Hard drive / SSD: mount in a bay (or M.2 slot), connect data (SATA) and power cables (or seat the M.2), then partition/format and install or migrate the OS.
• RAM: align the module's notch with the DIMM slot key, press until the retention clips latch; populate matched slots for dual-channel.
• CPU: lift the socket lever, align the CPU's marked corner/keying, drop it in with zero force (don't bend pins), latch it, apply thermal paste, and mount the heatsink/cooler with its fan connected. Then power on and confirm the BIOS/UEFI recognizes the new hardware.