I'd start by clearing the old program and starting over. It sounds like you're setting up a simple 4 channel plane so it won't take long anyway. Start by getting the servo horn on in the right place the way JohnBuckner described, then set your subtrims and endpoints as needed. You really shouldn't need much subtrim if you do step 1 right, but sometimes things will wind up a bit off even if you try really hard to get it right. If you still can't get any down travel in your ailerons, I'd suspect a bad gimbal in your transmitter.