Tiltrotor servo setup

I am setting up a VTOL tilt-rotor drone using 3 motors while one is “tilt-able”. I need help with the servo for this motor. I want to be able to autonomously do the transition when on a mission, and I want to manually transition for testing purposes. How do I physically connect the servo to the Pixhawk and how do I map it to a button on my Logitech gamepad using QGC?

Im curious about this too…