Welcome to bbPress!
I don’t know how familiar you are with forums, so I’ll give you a quick rundown. Typically how bbPress and other forum software works is you have the main forum and under that you have individual boards (In this case General Discussion and Off-Topic) which group discussions by topics. For example, this is a topic in General Discussion under the main Forums. You can reply to this topic and your response will appear below.
Feel free to play around! Create a topic, reply to this one, view the other board “Off-Topic”, etc. You can use the breadcrumbs above to go to the main Forums page and see the different forum boards I’ve created. I’ve only created two just to show you what having multiple boards may look like. In this case, there’s a General Discussion and an Off-Topic board. These boards can be called anything you want.
Sorry if this is overwhelming at all, if so, we can schedule a meeting and I can help explain everything in person, as that would probably help significantly.