You can find some MFC tutorials on the web - start with something simple, like making a window, then adding a few controls. You'll get the hang of it.
Again, I'm not against experimenting, but as Paul McKenzie said, if you insist on doing this to actually get a functional editor for your school project, then you're way over your head - your code already has some design issues as it is (as we pointed out) - even if it compiles.

Just find a tutorial and try it out - I mean, you're using functions like RegisterClassEx(...) while just knowing what it does, and not knowing how exactly it does it under the hood - and yet you are able to manage just fine. So, what makes you think you'll have overwhelming trouble with a higher level API?