just off the top of my head, here are some step by step instructions:
1.)find a thread that looks interesting
2.)click the link
3.)read all posts that are already there
4.)type your response to whatever is being currently discussed
5.)click "post reply" button
Comments
http://www.ehow.com/
That'll tell you how to do most anything, so it should probably answer your question.
1.)find a thread that looks interesting
2.)click the link
3.)read all posts that are already there
4.)type your response to whatever is being currently discussed
5.)click "post reply" button