After receiving the Goron Tunic from the goron named after you in Goron City, you can proceed to the Fire Temple.
Get a Key
Kill the fire keese and through the door up the stairs to the left.
After a cut scene, jump on the platforms to the left to reach a ledge with a switch on it. Step on it to free the Goron. Open the chest in the cell to get a key.
Get a Second Key
If you go toward the platform in the corner across from the Goron's cell in this large room and use the hookshot on the pillar to reach it, you will find fairies in jars that you can catch in bottles.
Go back to the first room of the dungeon, and go through the locked door straight ahead.
There is a bridge here, but don't go across yet. Instead, go left and walk along the wall. Go through the door under the ledge.
Step on the switch to free the Goron, and get the small key from the chest. Go back out.
Get a Gold Skulltula
Play the Song of Time near the edge of this platform. A blue block will move down to your level from up above. Climb up it and go through the door above.
Raise your shield and wait for the tiles to stop flying. Kill the Like Like. It can eat your shield or tunic, but if you quickly kill it, you can get those items back. If you lose those items, you will have to go to a shop and buy a new one. The Goron Shop in Goron City sells Goron Tunics. You can avoid getting close to the Like Like by killing it with arrows.
After killing the Like Like, kill the gold skulltula on the wall, then leave the room.
Get a Third Key
Go to the left and go around the edge of the room. You will have to step on the lava for a moment, but not long enough to get hurt. Continue around the edge of the room until you walk past a locked door. Keep going around the edge of the room to reach a ledge with a wall that you can bomb. Bomb the wall and go through.
Free the Goron and get the small key. Go back out.
Get a Second Gold Skulltula
Go to the right and go around the edge of the room to return to the locked door that you walked past. Go through it.
In here, walk straight until you slide down a plank. Turn right and climb up the fence until you are standing on top of it. Carefully turn around and kill the keese with the hookshot. Then use the hookshot where the Keese were so you are standing on that walkway. Jump down to the platform with the block on it. Push the block forward so it lands where the fire is coming out. Jump onto the block to rise to the upper floor.
Go through the locked door at the top.
Go to the left and climb up where you can see the Torch Slug. Kill it, then climb up the next ledge, kill the slug, then jump across to the ledge with the block on it. Push the block off, then jump down and pull the block until it stops. Climb onto it and jump across the gap, then climb up the shorter part of the fence on the wall to reach the lower ledge.
Throw a bomb at the crystal switch to stop the fire. After you throw the bomb, quickly run close to the fence so that you can climb onto the fence as soon as the fire disappears. Climb up the fence and go through the door at the top.
Go to the left, but be careful of the rolling boulder. Continue going to the left, then under an angled piece of wall, to reach what looks like an empty niche in the wall. Bomb the left side to reveal a gold skulltula.
Get a Fourth Key
Look away from the wall that had the gold skulltula, then go right, around the wall, while avoiding boulders. Go through the door in the niche to the right to find a trapped Goron. Free him and get the small key from the chest.
Get a Fifth Key
Back in the rolling boulder room, go straight, and make your way to the opposite side of the room. In the niche on the left, step on the switch to free the Goron and get the key. Then turn to face away from the Goron's cell. From this position, there is a locked door on the left wall of the room, near where you freed the other Goron earlier. Go through the locked door.
Get the Map
If you fall off of the bridges in this room, you will land in the large room with a bridge over lava.
Shoot the eye switch and go through the door that opens. Get the Dungeon Map from the chest.
Get a Third Gold Skulltula
Go back to the last room and go to the right to go through the locked door.
After you jump onto the fence above the lava, a wall of flame will follow you. Keep running across. If you jump over the gap to the other side of the fence, stay to the left to avoid the Bubble that will come up from the lava. Keep going until you reach the opposite end of the room. Jump to the ledges on the right and go through the door.
You are now on the upper level of the rolling boulder room. From the place where you enter, play Scarecrow's Song (read Before the Temple of Time to find out how to learn Scarecrow's Song and read Temple of Time to activate the song for adult Link if you haven't done so already). If a scarecrow does not appear on the ledge above you after you play Scarecrow's Song, move around and try playing it from a different spot. Use the hookshot on the scarecrow, then turn around and use the hookshot on the target to make the elevator go up. Go through the door at the top, then go around and climb the fence. Kill the skulltula and climb the next fence. Go through the door.
Follow the path for a short distance, then turn around to see a gold skulltula on the inner wall. Get the token.
Get 200 Rupees
Step on the switch, then run up the non-steep part of the angled floor. Use the hookshot on the post with the target on it, then run forward near the edge of the ledge. You will slide, then you can run to the chest that contains 200 rupees.
Get a Sixth Key
Go back to the boulder room. The elevator won't be there when you first arrive, but just wait a while for it to come up, then use the Hookshot on the scarecrow when it reaches the bottom. Or you can just fall down below, but you will get hurt, and you need to make sure to land on the raised platform rather than the lower area where the boulders are rolling.
Back in the boulder room, you should be on the upper level. Try not to fall below or you will have to go back around to the upper level.
Go to the big platform straight ahead, and bomb the cracked floor here. Climb down the fence and step on the switch to free the Goron. Get the small key from the chest. You will see a door up ahead, but don't go through. Instead, go back to the fence that you climbed down to get here, and climb back up.
Get a Seventh Key
Back in the rolling boulder room, jump onto the small ledge with the switch on it. Step on it, then jump onto the big platform nearby. From here, carefully jump onto the two narrow platforms to reach a big ledge at the other side of the room. From the big ledge, jump over to the Goron's cell and get the small key from inside.
Get the Compass
Jump all the way back to the platform where you bombed the hole in the floor, then go across to the ledge with the door in the wall. This leads to the room with the wall of flame.
Jump down onto the fence and go to the locked door up ahead on the right. Go through, then go straight through the hallway to the next room.
When you get close to certain poles in this room, a wall of flame will appear between them. Move slowly to avoid walking into the flames. Go right and find the door in the wall on the rihgt. Go through the door there to find the compass. Go back out to the large room.
Go back the way you came, going over the fence in the floor, and find the locked door in the wall to the right. Go through the locked door. In this small room, go straight across and exit the room.
You are back in the large room with the flame maze. There is a switch in the floor to the left. When you step on it, the wall of flame will go away temporarily. Find the safe path from the switch to the wall of flame, then step on the switch and go past where the wall of flame was. The door up ahead is fake, so bomb it to reveal the real door. Go through.
Use the hookshot to pull Flare Dancer's body toward you. Hit it with your sword, then try to get in front of it when it turns around, and hit it again. Run after it if necessary. Hit it when you can reach it. After it jumps back into the flames, repeat the process when it comes back out.
Get the Megaton Hammer
Jump onto the platform to be raised to the next floor. Go through the door.
Go around to the fence, climb it, then drop a bomb on the crystal switch down below. After it explodes, climb up the fence where the flames were. Go to the next room.
Use your arrows to kill as many of the fire keese in this room as you can, going around the outer edge of the room to reach the ones that are too far away. Step on the switch, then carefully run up the narrow stairs to reach the chest. Open the chest to receive the Megaton Hammer. You can pound the floor with it, or swing it left or right by holding the control stick when you swing it. You can do a jump attack with it as well. It can knock totem poles out of the way, it can make certain blocks fall, and it can activate rusty switches.
Get an Eighth Key
Turn around and go to the left, and go down to the lower area. Use the Megaton Hammer to hit the face block in the ground near where you entered the room. This opens a hole in the floor. Go down the hole.
Swing the hammer to knock the totem pole out of the way, and go through the door that was behind it.
Don't break the small crates. Kill the fire keese in this room, including the ones around the corner at the far end of the room. Pound the face block to create a staircase. Take a small crate down to the blue switch at the bottom of the staircase, step on the switch while holding the crate, set the crate down on the switch, then go through the door that opened.
Stand on the face block and hit it with the megaton hammer to go to the lower floor.
Turn around to see a rusty switch. Pound it and go through the door.
Go close to the edge and play the Song of Time to move the blue block down to the lower level. Use it to jump across to the other ledge. Hammer the rusty switch, then talk to the Goron and get the small key from the chest in his cell. Exit this room the way that you came in.
Get a Fourth Gold Skullula
Stand on the large face block and hammer it. You won't get hurt even though it's a long way down. Go back to the first room of the dungeon.
Go down to the lower part of the room, find the totem pole, then use the hammer to knock it out of the way. Go through the locked door behind it.
Kill all of the monsters in here and go through the door.
Raise your shield until the tiles stop, then kill the Like Like and get the gold skulltula. Go to the next room.
Flare Dancer 2
Kill this flare dancer as you did before. Open the chest to receive bombs. Go through the southern door.
Get the Big Key
Hammer the rusty switch to free the goron. Get the Big Key from the chest.
Reach the Dungeon Boss
Go south from here, then in the first room of the dungeon, go up the stairs, then go through the door on the left.
Jump across the platform in the center of the room and go straight to reach the Boss Door in the back of the room. Go through.
Jump across to the large platform with the nine holes in it, and go toward the center of the platform to start the battle. Throughout the battle, Volvagia will cause fire to spout from some of the holes, and its head will appear in the last hole that the fire came out of. Try standing near one of the corners of the grid so you can see all of the holes.
When Volvagia's head appears, run over and hit it with your hammer. If you wait too long, Volvagia will attack. After hitting Volvagia with the hammer, hit it with your sword, or with the hammer again.
Sometimes Volvagia will fly around the room. It's possible to hit it with an arrow at this point, but it's tricky. Avoid the fire that the dragon breathes at you.
If Volvagia flies straight up, look for shadows on the ground and run away from them. Boulders will fall where you see shadows.
Repeat the above strategy until Volvagia dies.
After you get the medallion, you can explore Death Mountain Crater.