I just looked it up on Google. The pictures show a standard GWS "Dream Starter" transmitter.

Those are called DIP switches, and they control the servo reversing, as 3DF says. To demonstrate what happens, turn everything on and move the right stick to the right. Find the servo that moves and observe how it moves. Now flip the #1 switch, and move the right stick to the right again. Notice that the servo now rotates in the opposite (i.e. REVERSE) direction.

Don't forget to set up the switches as described in the instructions. If you don't, your helicopter may do strange things, opposite of what you were expecting. That is, it could move forward when you tell it to go backward, right when you tell it to go left...