You should have a test server, provided by 101XP company. There is should be a game login page on the test server. Link to the game login page should based on 101xp.com subdomain. awesome-game.101xp.com, for example.
You'll need send to us you game API documentation and private keys for it or other data to make requests to game API
You'll need to prepare game server and game client to bind show of payment window with easyXDM integration