When downloading your first game, a pop-up will appear asking you to authorize the download of a game outside the market place.

1. Click on Settings in this pop-up.
   
2. Then tick "unknown source."
   
3. Then press OK.
   

The installation of the game will then begin.
It is 100% safe.
If you have questions, please call the hotline: 0-808-234-8679
Or send an email to android.support@gameloft.com