Floor 1 (13)

Head north, then east into a boulder hall.

Dodge the rolling boulders to cross the hall. Be aware that the supposed safe area on the left is a pitfall.

Once across, you will reach a gap with more boulders rolling east.

Shoot the eye switch on the north wall when there is enough space between boulders to activate it. This will open a room to the west.

Open the chest in the newly opened room to find a Green Rupee.

Warning: Three Stalfos will emerge from the sand.

Use Bombs to defeat the Stalfos quickly, as they will keep respawning (respawning: enemies reappearing after a short time) if you take too long.

Open the chest that appears after defeating the Stalfos to get a small key.

Head back east, then south down the boulder hall, and into the central room.

Head north, use the small key to unlock the door, and then head upstairs.