Upon entering the Earth Temple, go to and utilize the nearby Bird Statue. Then proceed to leap across the rock platforms atop the lava - don’t worry, they won’t sink into the lava, so take your time. Once you reach the safe ledge, defeat the Fire Keese and the Red Chuchu. Afterwards, dig around to find an air spurt. Ride it to the ledge, on which you’ll find a Red Rupee inside a chest. Head on over to the western room to speak with a Mogma.
Afterwards, return to the central area and go up the broken staircase. When the lava platform is lowered, get onto it then the other platform when possible. Once the second platform rises, get onto the other side. On this ledge, go to the two opposite sides of the platform and cut the ropes the mechanisms are using to keep the bridge up. Then launch your Beetle to the right of the bridge to find another such mechanism. After the bridge lowers, go to the other side.
In here, you’ll find a Lizalfos; defeat it. To the north/northeast, you’ll notice a structure absolutely covered with Bomb Flowers. Hit one with your Beetle or Slingshot to destroy it, sending the stone ball over to you. You can use it to cross lava by jumping on it. You can defend yourself atop it and even run over some enemies. Just do not move too much too fast; you’ll fall off into the lava.
Begin by heading to the southeastern corner of the room via the stone. Here, you’ll find a Mogma, Ledd, who lost his Bomb Bag and wants you to get it for him. Agree to help, then crawl through the tunnel in the gate nearby. Defeat the Bokoblin here, then dig up an air vent. Go to the upper ledge and around to collect Rupees. Afterwards, grab a Bomb Flower and roll it through the tunnel to the rock blockade outside, where it should destroy it. Go back through the tunnel and into the room hidden by the now-gone rock blockade.
In this room, defeat the two Lizalfos; shield bashes are a good technique to rely on. Afterwards, a chest will appear. Open it for the Bomb Bag, then go to the corner of the room for an Amber Relic. Leave the room and speak with Ledd to earn the Bomb Bag for keeps, as well as five Bombs. To get more, pick up a Bomb Flower and press B to store it; store some via the room nearby. After the restocking, use the stone to go to the southwestern corner of the room.
Here, you’ll find another platform whose height changes on whether the lava is rising. As it prepares to rise, throw a Bomb onto it to remove a rock blockade. Get on the platform next time around and open the chest for a Golden Skull. Take the stone eyeball to the center platform now. There, use the Bird Statue and go around, defeating the Red Chuchus. Afterwards, head up the western broken staircase. Throw a Bomb at the rock to clear the path, then head across to a Lizalfos. Defeat it if you want, then continue west into the next room.
In this room, head across the platforms and defeat the Bokoblins as you go. The Magma Spumes can be annoying, so a throw a Bomb at them should they become a nuisance. On the far end of the room, jump onto the lava platform atop the geyser when possible. Jump to the higher ledge and defeat the Bokoblins, then open up the chest for a Dungeon Map. Go back to the lower area and exit.