Servo to pixhawk 6c

Hi all
I just finished my drone build using the pixhawk 6c as per painless videos. All working great.
Now I want to add a servo for a release
Question is do I put it onto the fmu port or the I/0 port which have the motors. I would guess there would be a setting in mission planner that would have to be activated as well.
Have setup a channel on my tx16s for it.
Regards Dave

Put it on an output that is not in the motor timing group.

Then let’s say you have the Transmitter mix output on chan 8 to control the servo and you want to connect the servo to output AUX2/Chan 10.
Servo