It all depends on the plane. I believe most require elevator to spin. Usually to enter a spin, you slow the plane down and as it slows you keep adding more and more elevator to keep the plane at the same altitude. Obviously the pitch of the plane will change but you still want to keep it at the same altitute. Eventually, once the plane slows enough in conjunction with the angle of attack, one wing will stall (usually the left but this can vary due to cross winds etc). Once this happens apply up elevator and full rudder and aileron in the same direction as the stalled wing. To get out, you just release the sticks and immediately go to a little bit of down elevator to ge the plane into a good verticle downline.

In IMAC the wing MUST STALL in the manuever. The judges watch for the front of the plane to suddenly drop down. If they see an abrupt pitch upward before the spin, you loose points as you snapped the plane first to force it into a spin.

Hope this helps.........Mark