Follow the instructions in this website: https://ardupilot.org/dev/docs/building-setup-linux.html
Follow the instructions in this website: https://github.com/Intelligent-Quads/iq_tutorials/blob/master/docs/installing_qgc.md
In 1st terminal
- run ArduPilot SITL
$ cd ~/ardupilot/ArduCopter/
$ sim_vehicle.py -v ArduCopter
In 2nd terminal
- run QGroundControl
$ ./QGroundControl.AppImage