Replying to Half pipe help

This is the first year i have ever skied at an area with a pipe, and i really like it but i kinda suck. My main porblems are spining without poping, pumping the walls, and knowing what angle to come off at. When i try to spin i always end up at in the middle of the pipe. I know your supposed to pump the walls but i have no idea how to do it. if i go like 3 or 4 feet above the top of the wall how far in distance should i go? Any sugestions? Thanks