I got into the new Tower of Izyel today (the new instance dungeon)
Basically here is how it works.
You get a party (get a good one) and head into the tower at the Forest of Mist.
Basiclly u go from mob to mob fighting mobs in rooms. Each time u kill a mob u walk to the next room and kill a stronger mob. Bosses will pop up at different parts of the dungeon
Screenies