How to Get the Lens of Truth in The Legend of Zelda: Ocarina of Time

Learn the Song of Storms from the man with the music box in the Kakariko Village windmill shack when you are adult Link. Talk to him and then use your Ocarina.

Go back in time and return to the windmill shack as young link. Play the Song of Storms in the shack. The village well will drain.

Drop down to the bottom of the well and enter the dungeon.

Crawl through the small hole and climb down the ladder. Defeat or avoid the spider that drops down from the ceiling at the bottom of the ladder. Walk through the trick wall directly behind the spider.

Turn right once you are through the trick wall. Follow the main path through two left turns until you reach a Triforce symbol on the ground. Play Zelda's Lullaby on the Triforce symbol to lower the water level.

Return to the area you came to right as you went through the trick wall in step 4. Drop down into the hole in the floor that is right next to the trick wall and crawl through the small tunnel. Go forward, climb up the vines and enter the door.

Let one of the hands that is sticking up from the ground grab you. The boss will appear. Wiggle the control stick and tap the "A" button repeatedly to break free from the hands. Attack the boss when he lowers his head. Let one of the hands grab you to make the boss reappear if he goes back underground.

Defeat the boss and get the Lens of Truth from the chest that appears.