When you're typing in your message to post, you'll see a bunch of buttons above the text area. Experiment with them to see what they do.
For example:
[b][/b] will make your text
bold.
[i][/i] will
italicize your text.
[u][/u] will
underline your text.
Quote:
|
[quote][/quote] will quote your text
|
etc., etc., etc...