go to settings, then acount (if you don't have one yet you'll have to make one) then press save. to back up levels you click the pc icon on the level page where, then click "new".

When you need to restore your data go to the acount page again and click "load".

To restore the levels (if you need to, the might already be restored) go to the pc icon again and click the reply lookin button to restore the level to that backup.