Save your game by connecting it to Game Center or Google Play.

Game Center:
This App (preloaded to your iOS device) automatically saves in-game progress, also allowing you to access save-game data on multiple devices.
Game Center only supports one game per account!
Attempting to save more than one game to your Game Center account will result in lost data!
To connect, please follow these steps:
Enter device settings, find and select Game Center

Ensure that it is enabled
Tap on your apple ID
If you already have an account, go ahead and log in. If not, make yourself and Apple ID. (Follow steps on your Apple device)
Launch Game Center from your home screen
Find the game icon, and select it, launching the game from within game Centre
After loading, you should be prompted with a message reading "welcome back... your ID/Name"

Google Play:
Google Play only supports one game per account!
Attempting to save more than one game to your Google Play account will result in lost data!
To connect, please follow these steps:
Open the Google Play app on your device.
If you already have an account, go ahead and log in. If not, create one.
Launch Game and go to the Settings window.
Select the Google Play icon to connect your game to Google Play.