In order to transfer your Cloud save from one device to another, you need to first make sure you are logged into your Google Play or Apple account in-game on you first device.
Then install the game on your second device and make sure that you have access to a steady internet connexion.
Once the game is installed on the new device, log into your Google Play or Apple account in-game on this new device and wait for the synchronization to be complete.
Please make sure that you really wait until the synchronization is complete (the game will display a message if it is not) before you launch a run on the new device as otherwise it can overwrite your previous progress!