When you first enter Destiny 2 Prophecy Dungeon, there is a good chance that you will need a few minutes to get your bearings. The Tower map itself is not exactly clear; it only says that you will find out the nature of the Darkness.
The easiest way to describe the dungeon is that it is a collection of bosses and encounters. Each of these requires a different strategy to succeed. These encounters are not what we have typically seen from Bungie in that the solutions are not always easy to figure out. You and your teammates will have to put some serious thought into each fight and puzzle to progress through the dungeon, but the rewards you receive at the end are well worth it.
To activate the dungeon, you do not have to run around and complete prerequisites to start it. You only must go to the tower and press start.
With that said, the dungeon has a recommended power level of 1040. During the later stages of the dungeon, you will fight enemies with a power level of 1060. We recommend that you start the dungeon at 1050, but you can complete it with a lower power level if you know what to expect when you enter.