There are some c++ tutorials, but how does it help you to see those on YouTube?
It’s much better if you pull the old wiki out of a search and just follow the advice and tutorials people like Rama used to share on it once upon a time.
Realistically, the only way you’ll ever learn something is to either take apart something else.
Or to attempt to do it, fail at it, and do it yet again… by the 10th re-do or so, you usually have things down.
It’s time consuming. Sure.
So are other engines though.