Need help understanding the Codebase

[kingbass01]

I have been trying to understand the codebase and how it works but I don't think I am making any progress and everytime I open a new file it makes me more confused. I am getting errors in many files without even touching them but then also the app builds succesfully. The wiki also gives overview but can't help.
I tried these examples also :
Example 1
Example 2
But they also seem outdated because there is no info tab in the app when I ran it

I was also not assigned any mentor after filling CLA and feedback form to whom I can ask my doubts.
Any help regarding how to understand and start could help because I really want to contribute.
Thanks.