Forum usage is pretty cut and dried. You can create topics, reply to other topics and carry on a conversation until the thread dies of old age. As for bumping dead topics, don't do it unless you have something useful to contribute to that thread.
For instance, if you have encountered a bug that someone else was experiencing years ago and mentioned on our forum, please bring that thread back to life rather than creating a new one. On the other side, if you are just bumping a thread to say "thank you" or something non informative to the dead thread, do not post it. That will just needlessly bring a thread back from the grave and annoy a lot of users.