Proper PX4 to PM Board connexion


I’ve started to build a FX79. wing using px4 from holybro and I’m having issues properly connecting the PX4 to the PM to get all actuators and Motor to run.

I’ve tried all the I/O PWM OUT to IN and FMU OUT to IN connexion as described in the wiring QuickStart but can’t successfully move my control surfaces.

Here is a picture of the PM and it’s in/outputs:

the airframe reference is Flying Wing.
I can’t seem to understand the wiring of MAIN and AUX.

Any input on this problem?