You can only play your game on multiple devices if you have a Facebook account linked or with Apple ID account linked (Apple only).
To access your game on another device:
Facebook - just ensure you are logged into your Facebook account on the Facebook app and web browser and choose “log in” and “continue with facebook” from the main menu!
Apple ID - make sure both devices are Apple and logged in with the same Apple ID. Then when logging in on another device simply choose "log in" and "continue with Apple ID"
When playing across more than one device always make sure that when finishing a play session on one device you wait at least 20 seconds between the last action and closing the game. When you close the game, please ensure it is fully force quit before opening your game on another device.