Gerudo Valley, Fortress & Spirit Temple

The spirit sage

Chapter 15 of 16 of the Ocarina of Time remake walkthrough, played as Young Link, in 8 steps.

Jump the broken bridge with Epona, break into the fortress, cross the wasteland by following Poe lanterns, and visit the Spirit Temple as both ages.

Gerudo Valley: ride Epona across the gap (or Longshot the post). Enter the fortress and free the four carpenters: fight the Gerudo guard in each cell room. Receive the Gerudo Membership Card.
Optional: Gerudo Training Ground (10 Rupees) for Ice Arrows; Horseback Archery for a Piece of Heart and a quiver upgrade.
Haunted Wasteland: follow the flags to the stone hut, then use the Lens of Truth to follow the Poe guide to the Desert Colossus.
Enter the Spirit Temple. As an adult you can go no further than the entrance hall; leave and Sheik teaches the Requiem of Spirit.
Return as a child, warp with the Requiem, and crawl through the small hole. Clear the child wing (Bombchus help), hit the sun switch with the shield, and reach the hand for the Silver Gauntlets after the Iron Knuckle fight. Nabooru is captured.
As an adult, lift the boulder on the right wing. Solve the mirror and sun puzzles, beat another Iron Knuckle, and claim the Mirror Shield.
Reflect light onto the statue's face, fight brainwashed Nabooru (Iron Knuckle), and reach the boss.
Boss: Twinrova. Absorb one sister's beam with the Mirror Shield and fire it at the other. In the merged form, absorb three of the same element and release. Spirit Medallion.