OpenCV Python where to learn learning?

Question

OpenCV

There is a script on OpenCV python that can recognize differences in the scene.
There is an experience where I manually trained a script from a series of good / bad (but I don’t know how it was implemented, I just trained)
Can anyone tell me the source where such a case is more or less analyzed in detail, I want to study this issue and implement it.
I studied OpenCV
itself. The task itself is a scene where people change, but the studio should be the same. And I need to teach them that it can change, it doesn't.