In order to enjoy games on GoD, you require to download and install Games on Demand Player on your PC. This is one time downloadable program which will help you downloading and managing games for Games on Demand Service.
Note:
In case you have an older version of the player this will also update the player to a new one. The new player doesn't supports Mozilla Fire Fox 1.5 2.0 and 2.0.0.1.