A dialog box will appear. Under the Edit menu, pull down Preferences. Click on Addressing. Click both boxes, Address Book and Directory Server. Some people like to have a few lines added to the end of their messages that tells their name, title and perhaps a link to their web page.
Some people put a cute quote or other words of wisdom.
You could type this every time you send a message, or you can create a signature file and tell Netscape to tag this on at the end of every message you send. First create the file. Use Simple Text. Every computer on campus has simple text. You should click on your hard drive icon, click Applications and Simple Text should be there.