Click on the forum that you want to post to.
To reply to a topic, click on the topic you want to reply to. Then click "create reply". Replying top the "first post" is considered a reply to the topic itself.
You can use some HTML in your post (B, I, A)
You can only edit a post if you own the post, or if you are an administrator.
You should keep your email up to date by logging in, clicking Edit Profile and editing your email address. Accounts with invalid email addresses will be discarded.
Profile text can contain links, I/M addresses, etc.
Your email address will not be shown.
You can set your display preferences as well.