Email: Go to the upper left corner of the screen, the section with the icons, and click the button that displays your picture (in your case, a silhouette of a person). A window will pop up and you should then select "My Content", the third option in the right column. You will then be taken to a page that will has a list of sections on the right side. Select "Email & Password", the third option from the top, and that page will tell you how to proceed.
Avatar: Click on the same picture of a person and select "My Profile". On your profile page, go to the right side column and click the "change" button on the upper right corner of your picture. The window will tell you how to proceed.