The forum is divided into different sections which themselves contain forums containing more specific subject areas.
The main forum home page has a list of categories and forums with basic statistics for each including the number of threads and posts, the name of the most recent post and which member posted it.
Important threads are stickies pinned at the top of some sections by the moderators or administrators. These are topics thought to be important or of current interest
When you click on a forum that interests you, you will be taken to a list of topics that are thread headings. Each one is a conversation between members starting out as a single message which grows as different members respond.
When there are more topics in a section or pages in a thread than will fit on a single page you will see page numbers at both the top and bottom of the page.