After getting to the top of the snowy peak near the Gerudo city, you will find a small hut with a book inside. Read the book and you will get this quest about a hidden shrine. The book doesn't give too much detail, but once you locate the switch it will make more sense.
Walk over to the ledge near a large puddle of water. You will see a weird contraption on the wall. It may or may not be lit up red, depending on the time of day. I am not sure what the strict rule for the activation is, but I was there at dusk. It definitely won't be at night since a shadow is required.
Once the shrine switch lights up red, grab a snowball and walk over to the switch so that the snowball casts a shadow directly on the center of the switch. Once the switch is activated, the shrine will appear out of the ground over by the cabin.
The shrine itself (Suma Sahma Shrine), is very easy as it is just a chest with no puzzle.
Loading Text Editor