As part of the Xenophagus quest, you will need to figure out how to get out of the darkness as part of the exotic quest The Journey. The first stop, Emergence, talks a lot about Crota, but it's a bit of a trap. You need to head to the Anchor of Light to light lecterns.
Destiny 2 - The Journey - How to get out of the dark - Order of lighting the lectern
Head to the Anchor of Light, then go to the point shown on the map above. This is where you will begin this part of the quest. You need to collect the Light from the Strange Relic in the small building shown in the header image above. The exact location can be found on the map. Once you have it, you need to light six lecterns in the correct order.
The community did a lot of trial and error for this one, but ultimately the good folks at Raid Secrets on Reddit got it all sorted out. My hat is to them, and their incredible ability to expose Fate 2 secrets. The easiest way to show you the correct order to turn them on is via a video. As such, I have recorded where to go, where the Light is and in what order you need to light the lecterns. Check the embedded video above.
Once you have them all, you need to go to an area that will be marked on the map and interact with an item there. This will take you to the next part of the quest, called Pathfinder! We're also working on a full guide for The Journey quest here if you need help with other steps.