Connect your account to Plarium ID/ Apple ID (for iOS devices)/ Google account (for Android devices) or Facebook. This way you both save game progress and sync your devices. Here's how to do it:
1. Tap on the profile icon
2. Open the Connection tab
3. Use the connection you like :)
Now you can log in on other devices:
Choose one of the options in the same tab as above or right on the loading screen.