How do I know the classes I need to program a project, for example the camera driver?

Answer 1

Start at the site of the producer of the camera.
If the have a driver, which allows you to control the camera with code, they also will have code-examples.

Answer 2

First is experience. you think before what functions and variables needed.
For the less experienced, you just start coding and then you just go with it.

Suggest you to go through programming patterns.