Goron City
Climb up Death Mountain and visit Goron City
Run up Death Mountain Trail to Goron City
After talking to the guard in Kakariko, he will let you enter the Death Mountain Trail. It’s a pretty straightforward path up to Goron City. It’s the only place you can really go at this point. The entrance is just past a big circle of stones as you climb up the mountain.
Play Zelda’s Lullaby to enter Darunia’s Chamber
First, you must find Darunia’s chamber. It is as the bottom of Goron City.
Jump off the first ledge you see and you should be there. When you find the
door that wont open, play Zelda’s Lullaby on the Ocarina.
Play Saria’s Song to make Darunia love you
After he talks to you, play Saria’s Song in front of him.
Throw a bomb flower to break up the rock blocking Dodongo’s Cavern
You must now leave Goron City. Head directly to the right of the Goron City entrance (as you come out) to find a ledge with a bomb flower next to it.
You can do two things here, the first one is to throw a bomb to break open the rock blocking the entrance to Dodongo’s Cavern.
Grab the Heart Piece while you’re up here
Then, after you explode the rock blocking the entrance, you can also back flip on to the ledge above to grab a Heart Piece.
Now, you can finally enter Dodongo’s Cavern.