Start by clicking on your name, and select "My Profile" up in the right corner.
Click on "Email and password". Fill in your new email address. Enter your current password and then click "Save".
Confirm your new email
When you have clicked on "Save" above, an e-mail will be sent to the e-mail address you want to change to. You must confirm the email via the link sent to you. You do the confirmation by clicking on "Confirm email address".