Do you have a question about the HEX here3 and is the answer not in the manual?
Connect Here3 to flight controller CAN port and configure parameters via Mission Planner.
Configure CAN GPS compass for Cube Black/Orange using current stable firmware.
Configure CAN GPS compass using ArduCopter Beta 4.0.4 firmware.
Steps to enable SLCan mode in Mission Planner for PX4 firmware.
Tutorial on setting up RTK base/rover survey using Mission Planner and Arducopter.