This page explains how to find the Tahno O'ah shrine.
How to Reach the Shrine
It is recommended to activate Hateno Tower before looking for this shrine.
Be sure to have protection against cold. You can get Snowquill gear (which protects against cold) in Rito Village.
Go to Hateno Ancient Tech Lab (read Locked Mementos for directions to the lab) and walk up the spiral staircase to go up to the top of the tower at the lab. Then float north to the snowbank on the mountain.
From there, go northeast to where you can see a few trees on the map. When you reach the area with the trees, look for the cracked stones in the wall. Bomb them to find this shrine.
Treasure Chest in the Shrine
The chest in the shrine contains the Climbing Boots, part of the Climbing set of gear.