Replying to a post can be done by clicking the reply link at the bottom of any post.
Clicking Reply replies to just that post.
Clicking Reply to All replies to every post in the thread.
The posting tools which open for a reply are slightly different from the tools for a new discussion. The folder and thread title are already chosen and cannot be changed.
You can choose to post your reply to another user, other than the user who made the post you're replying to, by putting another name in
To box.
You can also view the message to which you're replaying, as well as view the entire thread by clicking the Review Thread link.
You can create your reply using the WYSIWYG editor, or by clicking the blue HTML button and entering your own HTML and CSS.
Note: The red arrow shows where the HTML button is located.
Once things are as you want, click Post.
Note:
If you have a signature saved in My Controls > Signature for the forum, your signature will be loaded into the Signature input box automatically. If you don't want to use that signature for the post, you can clear the box and no signature will show up, or you can edit it with the editor or by using the HTML button by simply clicking in the signature area. The signature box is not shown in this example.
The topic
Posting a New Discussion has the signature box displayed.