Slitherine

Yi Wen and Miguel made a video of me showing how to use the Online play facility of the game, which uses Game Center to connect to other players.

The complete video.

Or in more manageable chunks:

Game Center Overview
Signing into Game Center
Starting a New Game on Game Center
Receiving Game Center Invitation
Game Center Notifications
Auto Match on Game Center
Flexible Playing Schedule on Game Center
Common Issues with Game Center
Managing Games on Game Center