Check the manual for channel mix functions. I gave it a quick glance, but didn't see any way to mix rudder or aileron to throttle, which leaves two choices: remove the centering spring on the elevator, and use the right stick for left/right and throttle via the aileron/elevator (V-tail) mix function; or swap the wires on the potentiometers for the throttle and elevator (or just swap the pots themselves, if the wires reach) and use aileron/elevator mix to keep the drive/turn robot controls on two sticks.