You have to cross the lake right to fleetopia. Once you come across this rock, climb up and once you're on top silk soar to the hidden area.





Once there, interact with the tablet, which will give you the wish.

There are a total of 7 locations you have to visit to complete the wish. After you have done that you can beat the game normally to get a secret ending with the achivement attached to it.

This one is right in the arena where you first fight Moss Mother.



This one is right over the ruins of Bone Bottom.



This one is in the bottom right corner of the scorched fields.



This one is next to the locked house in Greymoor.



This one is right outside the First Sinner boss room in the slab.



This one is at the peak of mount fay.



This one is at the very peak of the parkour section in the area above the cradle. To get there you have to silk soar up a hidden hole and enter the door. Inside of the door there is a liner platform section you have to complete, he is at the very top of it.