How do I begin to attend classes? I know I’m supposed to make ten posts but what’s the difference between that and replying to a thread?

Classes will begin once you've made 20 posts and have been online for 10 days. There is no difference to posting and replying - if you're trying to get quick posts, you can just head over to the games room, and such will have the same effect as a reply. Once all these requirements have been fulfilled, you will get a Report Card in your drop down menu - this is where you'll do homework. GL!