You can change your email address by clicking on your name in the left hand menu and selecting "Your Account".

On the "Profile" tab, select the "Edit Profile" button, then enter your new email address.

To save the change click the "Save" button in the top right.

To complete the change of email process, you will receive an email to the new email address to confirm that your email address exists.

Open the email that you should have received and click the "Confirm my account" button in the email.

Your new email address should now be confirmed and you can use it to sign in!