The ESC should go on CH3 and the rudder is on 4. First remove the motor from the heli, and also remove all the other servo connector. You only want a connector from the ESC on CH4 on the RX in order to test the motor alone. Turn TX on with throttle stick at the lowest position and wait a few seconds after you connect the pack to the ESC, now move the throttle stick slowly and see what happens, if not you may want to go back and reverse the CH4 and try again.
Good luck