To enter/use the actual forum,
Click on highlighted Topic or Forum Titles
You may make new topics, new posts, and new replies, plus you can delete your own new posts or replies, but not your own topics (since other people may have started discussing the topic). Be sure to subscribe to topics you are interested in following. The prompt to do that is at the bottom left of every topic or post.
If you’d like to MENTION another user, you can check out the Members tab (in the MENU below), and type the user name as follows, somewhere in the text of your post (@lindawing) (to get my attention). All MENTIONS will receive an e-mail alerting them to your post.