Courses and classes for a language institute

So here’s my scenario: We have 3 main levels: A, B, C. Each of those has sublevels, for instance A1-1, A1-2, A2, B3, C3. Some of this have two different timetables (If I didn’t get the concept wrong). I know this may sound a bit vague or wide, but I bet you guys with more experience than me or, the admins will understand my questions.

I was thinking on doing the following: Go to Courses and Classes Management and create the different Courses. So, here is where I should create the different courses, right? Like A1-1, A1-2, A2, B1… I should also be creating separate courses for intensive courses, if I have any.
Next comes “Classes”. I can manage hem from within each Course editing. But I don’t get this concept either. What are Classes? Maybe in this scenario I don’t need this?

Thanks a lot in advance!!!

This is a duplicate of Closing this post.