This page explains how to find the Jitan Sa'mi shrine.
How to Reach the Shrine
Be sure to have protection against cold. You can get Snowquill gear (which protects against cold) in Rito Village.
You will also need a bow and some arrows. You can purchase arrows in villages, or collect them from enemies.
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, make your way up to the peak of Mount Lanayru. You will see a dragon on top of the mountain. Go to the spring near the top of the mountain, and the goddess statue will ask you to free Naydra from the Malice.
Shoot one of the big orange eyeballs on the dragon and it will start flying around. At this point, look for updrafts around the peak of the mountain. When Naydra is coming toward an updraft, float in it. One of the orange eyeballs on the dragon will go past the updraft, so you can shoot at it while you are floating.
If you ever run out of stamina, just open your Paraglider again. Your stamina meter will automatically be refilled (only while Malice-Naydra is flying around).
After you shoot an eye, the updraft disappears, and Naydra moves farther down the mountain. Follow Naydra and get in another updraft to shoot another eye. Repeat the process until you have shot all the orange eyes.
There will be a cut scene. The goddess statue asks you to shoot Naydra. Don't worry: you can't actually harm Naydra. After you shoot Naydra, a scale comes off (no matter which part of Naydra's body you shoot) and lands in the spring. Pick it up, then drop it in the water near the goddess statue. The door behind the statue will open and you can access the shrine.
Treasure Chest in the Shrine
The treasure chest in the shrine contains a Frostspear.