There are two basic ways to set up ailerons.

1/ Using one servo, mounted in the center of the wing, with each side of the two arms on the servo activating each aileron. One goes up while the other goes down. This takes up just the one channel (normally channel 1)

2/ Using a servo in the middle of each wing half, with each aileron being actuated separately. This set-up uses two channels (normally channels 1 and 6 )

They are both good, but the second choice (using two servos) has the advantage that you can program the radio to operate the ailerons as flaps too, by moving them both down together, as opposed to one up and one down.

Hope that helped!

-David C.