Pixhawk 2.1 main out nor working

I have a pixhawk 2.1 and rc car. I want to use two sections that car. first manual wiht rc and second autonumus.

I connected rc car motor driver and servos to pixhawk “main out 3 and 1”. I drive throot and steering wheel on remote control. but It does not move :frowning: how can I set outputs (main out)?