Heart Storage is one of the Chamber Dungeons found in Link's Awakening.
Heart Storage is the tenth Chamber Dungeon unlocked in the game. It one of four of the 'Level 3' Chambers. The chamber dungeon is unlocked after Link completes the Stair Decisions dungeon.
The dungeon is shaped like a bottle and there are no pre-placed tiles or requiresments. Link will need to place all 23 tiles so that they connect. The trick with this particular dungeon is that when playing through the arranged dungeon, it becomes a 3-heart challenge. Link is only given 3-hearts, so it's best to arrange the dungeon with the least amount of enemies or obstacles.
Link will earn an Empty Bottle for arranging and then completing the dungeon. Completing the dungeon is also part of unlocking the Sheated Sword dungeon. Link will also need to complete Eagle's Tower.
Once you've filled the "bottle" with chambers, you gotta get through the whole dungeon with just three hearts. Now, I'm not here to tell you how to arrange your dungeon. But you'll wanna skimp on the monsters.