Place your throne somewhere, then place the bas drum in front of you right foot, and the hats in front of you left ( Vica versa if you're a lefty ) Okay.
The snare drum, placeed between your legs. The height of the chair, shoulden't be too low or too high, mess with that until it feels right. Usually when they a little above paralel to the floor. Lower means that you can't move your foot that much because it's cranked up.
Place the floor tom to your right, and the racktom(s) on the bass drum mount or stand.
At this point you want to be sure that you can reach everything with your bare hands. If not you will get exhausted very easily.
The ride cymbal is usually to the right, but i have seen people putting them anywhere, and also having multiple ride cymbals in both the left and right side. The crash/splash or anything like that, is usually placed to the left, but again. Can be placed anywhere.
Gongs are placed to the very right of you or behind you - that's what i've seen.
A cowbell HAHA, is mounted to the bass. - i have no cowbell.
Hope it helped - elseways i've been wasting my time