you simply envite your 3 other members (for light party) or 7 members (heavy party) and then the leader selects the dungoen in the DF and select join. The whole party will put put in. If its complete for the content (ie Sastasa is a 4man party) you will autocatically get in and can choose ANY combinations of classe to go; if you have to pick up a random player or 2, you will have to abide by the 1 tank, 1 healer, 2 dps party construction. I advise NOT to que as 2 dps if you dont have at least one of the other 2 with you.