you are talking about the tilt adjustment right?
Just tighten that down until the seat doesn't move. Alternate between the front and rear bolt till its just about right. Then you can fine tune the tilt by just tightening/loosening one or the other till its perfect.
Once its tight, its easy to make adjustments to tilt. Turn out a 1/4 turn on one, and tighten a 1/4 turn on the other.