how do i get those avatars on the bottom of my user name?
From the link that says "more info" next to where you can choose an avatar:
"Here's the list of currently available avatars:"
There are none, so that rules out that option. 
If you have more than 30 posts, you may also specify your own custom avatar."
When you hit 30 posts, you can upload your own.
thank you for your help.