Basicly you draw your avatar, fighting somone elses avatar, However at the moment theres a thing called "the plot" where some avatarists are taking turns to draw a series of comics/drawings to link into one big story/plot.
somthing about the amulet to control all dragons & the 5 keys to unlock it, and the race of 2-3 partys to get/seal the power.
But you don't have to take part in that if you don't you can just draw your avatar fighting somone elses avatar.