Congratulations you did it...lol Seriously what are you wanting to post? Click on the Forum tab and then find your subject. To post a new thread click on the "post new thread" button.
If you would start a thread on a given forum , use forum on the toolbar at the top of page (between the box "home" and the box"what's new") and scroll to the forum you want. Click on it and look for an orange box top left that reads" post new thread". Click it to start a thread.
To reply to a thread , click "reply" or "reply with quote" at the bottom of the conversation box you read.