Hello, I have a question. pixhawk2 hereLink remote controller

I want to connect the gimbal to the pixhawk2 hereLink remote controller

my gimbal is [TAROT] GoPRO T3D-V Gimbal
All you have to do is move up and down.

Please tell me how to assign a channel
I’ll be waiting for the reply. Thank you.

You may have a look at the ardupilot wiki
The Herelink don’t directly control the gimbal, but via autopilot