APPLE/iOS:
To play on multiple iOS devices, please make sure you are signed in to the Game Center in the game's settings. Then, sign in with Game Center on the other device using the same Apple/iTunes account. Your progress will automatically be synchronized.
GOOGLE PLAY/ANDROID:
To play on multiple Android devices, please make sure you are signed in to Game Services in the game's settings. Then, sign in with the Game Services on the other device using the same Google Play account. Your progress will automatically be synchronized.
If you want to link a game from an Android device to an iOS device (or the other way around) please be sure to Submit a Ticket for help!