First you will need to create a Google Play Games account which will back up your save data and store your achievements:
Then, you will need to ensure that you are signed in via. our app:
a) If you are playing Dream League Soccer, navigate to "Options" > "Game Settings" > "Advanced" and ensure "Google Play Games Services" is ON and "Google Play Cloud" is ON.
b) If you are playing Score! Hero, navigate to the settings menu accessed via. the navigation bar and ensure "Google Play Games Services" is ON and "Google Play Cloud" is ON.
Then make some progress in the app such as playing a match/level whilst connected to an internet connection, preferably Wi-Fi to ensure that the save data is uploaded to the cloud.
Then simply sign into the same Google Play Games account on the same or another device in the app and the save data should be automatically downloaded.