RAM is plug and play, in other words you simply plug it into the proper slots on the board, boot the PC and the BIOS and OS will recognize it. No special tools are needed, the RAM is held in the slots by little "tabs" on each end.
The important things are:
1. Type of RAM. There are several types depending on the age of the computer, over recent years the most common types have been EDO, SDRAM, Rambus, DDR, and most recently DDR2 and DDR3. They all are slot specific, make sure first the ram fits into the slot on the board. There are locking tabs of some type on each end of the slot that secures the ram into place as it goes into the slot.
2. Speed and latencies. Each type of memory also has specific speed and latencies. While mixing...