Mavlink communication between two Pixhawks via Sik telemetry radios

Hello , I am working on a project that consists of sending a vehicle( with Pixhawk 4 mini) position data via telemetry (mavlink) to another vehicle (with another pixhawk on board) , without having a Ground Control Station (GCS) in the loop and using the ardupilot software. I have read through the mavlink developer guide , generated the header files in C++ . The main issue i am facing is that I do not understand how to read data from a serial port in ardupilot. I have tried using the AP_HAL library UART sketches to read data from the port but i have not succeeded yet. Any advice regarding how to proceed is appreciated.

You can refer to this blog for some techniques

I see that a follow script has been added recently: