Hi Janet!
Welcome.
Adding the avatar is really easy.
Click on "My Profile" - it's one of the options listed at the top of the page.
Scroll down and you'll see where you can add a signature if you wanted (this will show up at the bottom of every post you make).
At the bottom of the page will be the avatar section.
Click on "Browse."
Find the picture file on your hard drive and select it.
Click "Update Avatar" and you'll be all set.