Connecting your account with Facebook is probably the safest way to keep your progress untouched, without worrying about changing devices or unfortunate events related to your phone or tablet.

To link your profile with your Facebook account, select the ‘Social' icon and select the 'Facebook bonus' banner on the left side of the screen.  
Then please tap the 'Connect to Facebook' banner and enter your login details. Once you confirm the connection, you will get a Coin bonus.
The Facebook bonus can be received only once. Please note that once you have synced your account with Facebook, it is not possible to log out of it or swap profiles. After logging in the new device you will be able to restore your progress.