HERE'S HOW IT WORKS
Sign in via facebook
Simply click on the 'Sign in via facebook' blue button found on the top o the page.
Select a cover you like
After choosing a cover, click on the 'Use as cover on facebook' blue button.
Save on facebook
Click on the green 'Click here to change the cover now!' button and save the cover as your facebook cover.
3 CLICKS, NEW PROFILE COVER!