Relay and AUX Pins on PX4

Hello All,

I am trying to configure my PX4 with relay switches that control the direction pins for my pololu 24v13 motor driver but I do not know how to activate them or use certain pins. I am building a rover with skid steering enabled and have configured the motors to work for either side but I want to be able to reverse them using my xbox remote connected to my laptop and Mission Planner. I have tried researching the pins for the PX4 but I can’t understand them nor find a way to see which relays to use for Skid Steering. Is there a good guide or pinout chart for the AUX pins on the PX4 for relay switches?