Wrong thread if i'm honest. I'll tell you the answer though, add them to your Friends List. Make sure your both online and go to a room like Fight Club or an event your both in. Find your friend and challenge him.
Urban Rivals | Free Online Manga Trading Card Game | TCG | MMO
The Urban Rivals team is made by lovers of all kind of Collectibles Cards Games and Trading Cards Games like: Magic the Gathering, Dominion, Vampire, Yu-Gi-Oh!, Pokemon, Wakfu TCG, Assassin Creed Recollection, Shadow Era, Kard Kombat and Might & Magic Duel of Champions.