As you make your way through Genshin Impact, if you explore Mingyun Village in Liyue, you will find a ghostly looking chap who needs some help. Speaking with him to start The Tree Who Stands Alone quest.
The first step in the quest asks you to look around the village. The search area is quite large, but you are looking for the hut shown below. It is in the south of the village. Inside you will find a book. Interact with it to progress the quest.
Now, you will need to find four wills that are hidden in different areas.
The first will can be found in a cave near a small pong to the south of the hut. Inside you will find a Luxurious chest, some resources, and the will. When you pick it up, a ghost will appear and speak with you.
From there, head northeast and you will another cave. Once again, the will is inside. This cave is filled with rare resources that you should definitely take the time to farm.
To the northeast you will find another cave, this one is located in a mountain you will need to walk around. Go inside the turn right and follow the tunnel to find the will. Once again, this cave is filled with valuable resources you should farm up.
From there, head to the northwest again and you will find the next cave entrance on the far side of the cliff. Go go inside and clear out the enemies, then swim through the tunnel and turn right to find the will.
Now it is time to head to get the treasure by following the new waypoint. When you arrive there, you will be set upon by a group of bandits. Take them all out, the dig up the treasure.