Struggling with modifying QGroundControl source code

Hi folks,
I need to edit QgroundControl’s video player for needs of my project. However I’m struggling with the task, since the app is like 300000lines of code. I cloned the QGC repo from github and successfully built it on ubuntu 22.04, but can’t find any tutorials/guides online what to do next.

Will be glad for any help :slightly_smiling_face: