The right one controls roll and pitch and the left one controls yaw and throttle. Recall that throttle adjusts the altitude, and yaw allows you to rotate it in either direction. Then there are trim buttons with each stick that are used to balance out the controls.
You will need to fly your copter by pushing the throttle stick upwards and then see if it tilts automatically or flies itself to some direction without you even pushing the other controls. When this happens, you will need to use the trim buttons on your transmitter to adjust the controls.