Lossen bolt, adjsut seat, tighen bolt.
Sorry, couldn't resist. That it a one bolt adjustment, lossen the bolt until every thing is loose, but don't remove it completely. Then you can adjust the tilt, and fore and aft. Tighten the bolt and your done. If you just want to adjust the fore and aft, you don't have to get it as loose as you do to adjust the tilt.
I much perfer these against the two bolt design, these are much easier to adjust. IMHO.