To move your account to a new device, or to play on multiple devices (just not at the same time) you first need to link your account with Facebook.
  • Tap on your FLAG (top left)
  • then SETTINGS
  • then ACCOUNT
  • and 'Login With Facebook'
Once you have connected with your Facebook account you can start the game on a new device. In the tutorial, when Duncan asks you who you are, instead of designing a character select 'I already have an account' and sign in with Facebook. You will then load your game onto that device and can alternate between devices to play.
 
We will be adding more methods to connect accounts soon!