On the Admin Dashboard, click on "create a new project".
Decide if you'd like your game to be "Public" or "Private". A public game is accessible by all, whereas a private game can only be accessed by players the admin manually invites themselves.
Decide if you'd like to allow guest players to play your game. You will not be able to track guest players' activity, and your game must be Public if you check this box.
Upload a game icon.
Give your game a name and a description.
Decide on your game's game code. See: What is a game code?