• Click on your picture in the top-right hand corner (if you've never changed it, it will be a silhouette)
• Click on 'Profile'

• On the left hand menu option click on 'Profile

• Use the diagionally facing arrows to widen the screen if all options are not displaying for you

• Click the 'Picture' link to change your picture
• Click the 'Edit' button to change your personal or contact details

Video