Step 0. Install ArduPilot library by following the tutorial below
https://docs.google.com/document/d/1OgCC17BiFaRYml6ymLix7IrCFkasUEywPy2u3vIW_HE/edit
Step 1. Clone official MAVLink repository
git clone https://github.com/mavlink/mavlink --recursive
Step 2. Replace the example/c folder with the custom repository
git clone https://github.com/sychoo/MAVLink-C-Library-for-ArduPilot
Step 3. Build the demo.c program by invoking the Makefile. In the case that it doesn't work, simply executing the command within the Makefile
make
Step 4. Run the compiled program
./build/demo which will simulate the ADS-B signal that will be sent to the drone.