Once the drives are installed into the case you are pretty much ready to boot up the computer for the first time.

If you have a seperate video card, now is the time to install it, but many motherboards have on-board graphics. You may also install any other cards and ports now, but it is generally better to boot up with the simplest possible computer configuration, adding other computer parts later.

Connect keyboard, mouse, monitor, power leads etc. Turn on the monitor. Boot up the computer - keep an eye and ear out for anything that seems wrong - strange noises etc - pull the power if you suspect anything amiss.

Check all fans are working, lights are operating correctly.