Here's a link on
How to add tickers and pictures (How to add tickers and pictures to your signature. How to post a picture.)
As far as posting if you want to comment to a post you can either type your reply in the box at the very bottom and then click the button that says add reply.
If you want to quote what someone else has said in your reply click the little quote button underneath their post and then click the brown button with the pencil and paper that says add reply.
If you want to start a new topic, just click the button that says "New Topic" at the very top of the boards.
If you look at the little coffee cups that are to the right of the posts on the forum page you will see a spoon in the coffee cup if it is a post you have already replied to. If no spoon is there then you have not replied to it.
I think that is the basics.