Yea, we use trampolines a lot at woodward for dry land training and such. You actually don't want to get a running start or anything like that to spin, ideally you want to be bouncing centered on the tramp and try your spins from there going straight up and back down right were you took off from.
If you find yourself drifting from your starting point a decent amount chances are you are taking off to early and want to wait slightly longer before you initiate the spin.
Once you get comfortable just bouncing in general and spinning try pretending the foam is "down hill" and get in your stance and try the same stuff like you would if you were on snow. So instead of your upper body facing the pit you would have your shoulders perpendicular to it.
If there's anything in particular you are having trouble with or want to work on let me know, I coached people of all ages on the trampolines alllll winter this year at woodward at copper so I picked up a few tips here and there.