Step 2: The processor
Before fitting the motherboard inside the computer case, it is best to first mount the CPU, the CPU cooler, and the RAM onto the motherboard. It is much easier to access everything with the motherboard outside of the case.
Intel processors from recent years no longer have pins, they are located inside the socket instead. Mounting the processor works as follows - raise the lever(s) at the side of the socket, then flip up the little metal frame. Sometimes there is a protective plastic cover here. If so, remove it. Now you can gently press the CPU into the socket.
Please note that the pins are very fragile, and that the processor only fits in one direction. Look where the corresponding ridges are in the socket to find out in which direction the CPU needs to be placed. Once the CPU is firmly in place, flip down the metal frame and slide it back into place. Lower the lever so the processor is locked in.
AMD processors still have the pins on the processor. Mounting an AMD processor works as follows. After raising the lever, find out which corner of the CPU has a little white arrow, then line it up with the white arrow on the socket. Gently but firmly press the CPU into the socket. Lower the lever to lock your processor into place.