Tom, it's easy enough - once you know how.
Go to the Forum's home page and select "Introduce Yourself". It's the second thread down from the top. Once there you should go to the far right of the page and select, under "last post", the "re: Introduce Yourself". That's going to take you to the most recent post (obviously). Look around and you'll find the button labeled "Reply". I know, it's not marked "Start" -- but trust me, you do start there.
Give it a try -- and thanks for joining the Forum. If you haven't -- well, that's why you can't post anything yet. When you join/when you joined -- please also fill out your location. City/state is fine. We like to know something about where you are.
Jon a/k/a Seldom Seen Slim