This page explains how to complete the level 84 Endwalker quest "Helping Hands".
This quest is available if you have completed the quest In Shadow's Wake.
Starting the Quest
Talk to the Watcher in Mare Lamentorum to begin the quest.
Speak with the Watcher
You can optionally go southeast into the building and go down the ramp, then exit the building and go to the quest icon from there. Otherwise, go northeast off of the ledge.
Go northeast to the bridge near the central crater (zoom in on the map to see where the bridge is if you are having trouble finding it; its location is X: 20.6 Y: 30.8). Follow the path through the cave. When you are back outside, you will need to first go south along the edge of the chasm before you can go northeast to where the orange arrow is pointing in the minimap. Talk to the Watcher to proceed.
Speak with the Watcher Again
Go northeast, then enter the cave. Go to the quest icon on the map and talk to the Watcher to proceed.
Suffuse the Lunar Spongoi with Aether
Go to the quest icon and check on the sparkling Lunar Spongoi. There will be a cutscene.
Speak with the Watcher Once More
Go southwest to exit the cave. Then go northwest to where the orange arrow is pointing in the minimap. Talk to the Watcher to proceed.
Speak with Y'shtola
Talk to Y'shtola and say Yes to proceed. There will be a cutscene.
Speak with Thancred
Go north to where the orange arrow is pointing in the minimap. Talk to Thancred to complete the quest. There will be a cutscene.
Next Main Scenario Quest
After you complete the quest, talk to Thancred to accept the next quest: A Harey Situation.