I am not sure about Herelink, but maybe the procedure for a typical radio setup helps already.
The usual setup is that you assign a switch (2-pos. or 3-pos.) to a radio channel and in ArduPilot you set RCn_OPTION = 300, so that the script knows to listen to that channel. Then configure the script parameters and fly. It is also described here: Quicktune Readme
[Edit] I assume you want to use it for a drone (or VTOL plane), right? If not ignore this post 