I'm sorry, but we can't teach classes here. If I were familiar with a proof-theory site, I'd provide a link so you could find lessons and classes online, but I'm afraid I don't. (Note to fellow tutors: If you have links you'd like to recommend, please reply here and/or PM me. Thank you!)
Please post the specific exercise with which you're having difficulty, showing what you've tried, and saying where you're getting stuck, and we'll be glad to try to help you move forward. Thank you.
Eliz.