In the main menu, tap the OPTIONS icon (upper-right corner near the Gameloft icon). Go to Gameloft Connect > Connect and choose a social network you want to connect to.

Note:
* This option will be inactive if you are underage according to your region's data protection regulations.  
* You can’t link an SNS account to more than one game account.
* The Windows version doesn't have an option to connect with Facebook or Google Play.