Anyone looking to participate in a game must establish a game connection. They can do so by clicking their profile picture, and going to Settings
Once you have done this, there should be a list of options on the left hand side. Click select Connections to begin.
Select "Add Game Connection" Here you can select your game, input your in-game name (your username), your rank, and a link to your game profile. You can add more games with the by selecting "Add Game Connection" again.