Right now the game server integration is missing, i hope we can get it working soon. The way it is supposed to work is you get on the official EU or NA duel server and just duel. The ranking is based on ELO (http://en.wikipedia.org/wiki/Elo_rating_system) with a few modifications and we will most likely need lots of tweaking to get it right. The rankings page will be updated once a day based on the points you got.