I've navigated, a few BB styled forums, in the past. There's a 'Quick Links' at the top, where you can see 'today's posts'. There's the New Posts link, at the top, where you can view new posts, since you last logged in. Scrolling up, and down, you can get a feel for the forums, that you feel most comfortable in, and frequent those. The threads that you've read, will no longer be in a bolder color. You can return to your profile and see, where you've posted, so that you can return there.

It takes time.