You can mount the Pan/Tilt mount wherever you want on your drone. You may be limited in range by the length of the MIPI CSI cable that comes connected to the Google Coral Camera on the NavQ. You can purchase a longer cable from here:
Low Voltage Labs - Raspberry Pi Camera Module Cable FFC FPC Ribbon 15-pin (50cm)
The UBEC needs to be supplied power from the included power distribution board - you can solder the +/- wires to any of the leads on the board.
This image is from the NXP Cup Gitbook, so just use this as an example. Your Power Distribution Board will have bullet connectors on it.
Mount the Pan/Tilt mount anywhere you'd like on your drone. Plug each servo into the #5 and #6 PWM channels on the FMU, and plug the UBEC into the BEC port.
Make sure that your UBEC is set to 5V.
Setup in QGroundControl
These are the settings you will want to use in QGroundControl to control the servos.