As my title says, Ineed a crash course (pun intended) on what the control surfaces do on a plane. For example I fly a three channel parkzone vapor. This is my first plane. It has a rudder and elevator. Obviously, when I use my rudder it turns. That's easy. When I push up on my elevator, the plane fly's down and when I push down on my elevetor, the plane flies up.

Now, what does the ailerons do.Or better yet, what is different on a four channel plane.I believe that the ailerons are located on the main wings. Do they move independentaly of each other, which requires two servos, or do they move the same much like both sides of the elevtor?