You can add friends to play with in the following ways:
1. Add friends in the game using the game identifier (Support ID) that players post at the official game community on Facebook here: https://www.facebook.com/355886191166202. To redeem a code, go to the Friends menu → Invite Friends → Add Friends by ID. A number of invitations you can send is unlimited. You can also find your friend code in the tab mentioned above.
2. Add friends from Game Centre or from Facebook.