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 jump and hookshot onto the platform at the right side of this large room, 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 around the room to the left. 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 and 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 through the locked door that you walked past.
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. Jump down to the platform with the block on it. Push the block over. Jump onto the block to rise to the upper floor.
Go through the locked door at the top.
Climb the ledge to the left and kill the torch slug. 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 from it onto the fence on the wall. Climb up.
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 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 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 to the opposite wall. In the niche on the left, step on the switch to free the goron and get the key. Go through the locked door on this level.
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 through the door that you haven't gone through yet.
After you jump onto the fence above the lava, a wall of flame will follow you. Keep running across until you reach the opposite end of the room. Climb up to the right and go through the door.
You are now on the upper level of the boulder room. From the place where you enter, play Scarecrow's Song. If a scarecrow does not appear on the ledge above you, 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. Exit this room, then go around and climb the fence. Kill the skulltula and climb the 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, so you will have to fall. 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.
Get a Seventh Key
Climb back up. 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 door into the room with the moving wall of flame.
Jump over to the locked door on the ledge to the left, and go through. Go straight through the hallway to the next room.
When you get close to certain poles, a wall of flame will appear between them. Move slowly to avoid walking into the flames. Go right and go through the door there to find the compass. Go back out to the large room.
Go to the left side of the room, avoiding flames. 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 safe path to the switch near the far wall on the left. Be sure to memorize the safe path, then step on the switch and go around to the ledge where the wall of flame turned off. The door up ahead is fake. 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.
Climb the fence, bomb the crystal switch, and climb up the fence where the flames were. Go to the next room.
Use your arrows to kill as many of the fire keese as you can, going around the outer edge of the room to reach the ones that are too far away. Hit the switch, then 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
Jump down and hit the face block in the ground near where you entered the room. You will fall to the room below.
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. Pound the face block to create a staircase. Take a small crate down to the blue switch at the bottom of the staircase, then go through the door that opens.
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 get the small key behind the goron. 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.
Hammer the totem out of the way and 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 to the next room.
Get the Big Key
Hammer the rusty switch to free the goron. Get the Big Key from the chest.
Reach the Dungeon Boss
Return to the room with the boss door. Go through.
Jump across to the large platform with the nine holes in it. 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.
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.
Death Mountain Crater
Now that you have the Megaton Hammer, it's time to collect some things around the crater. Those red boulders that can't be bombed can be hammered to pieces. From where you're standing, cross the broken bridge, and then hookshot one of the wooden posts on the ledge across the way to get back to the other side.
Near here is a cluster of the red boulders, so hammer them out of the way and go into the passage. It's another great fairy fountain, so play Zelda's Lullaby and your magic meter is doubled.
Also, when you exit the fairy fountain, there's a boulder on the ledge to the right that you can hammer out of the way. From that ledge you can jump across, and continue to make your way to the big high ledge by breaking more boulders. Once on the big ledge, you can climb down the rock face where it drops off into the volcano, and you can climb down the wall. Somewhere in the middle of the wall there's a little nook with a piece of heart in it.
From here, exit the crater to the mountaintop where Biggoron sits. Get down to the level where the eruptions used to be, and hammer the first boulder you see to pieces. Then turn it to night, and a gold skulltula will appear there. Get it.
Then follow the path down the mountain until it opens out to the left. Carefully drop down to the ledge below, and go to where you threw the bomb flower to open Dodongo's Cavern. Hammer the rock to the right for another gold skulltula.
If you didn't complete the Ice Cavern at Zora's Fountain before, you're going to have to do it now. Refer to the Ice Cavern section to find out how to complete the cavern. You'll also need to have the blue tunic so you can breathe underwater; you get a free one from King Zora after you use blue fire from Ice Cavern.
You may now have 50 gold skulltula tokens, so go visit the creepy house of skulltula in Kakariko and get the reward for breaking the curse on the fifth person: a piece of heart.
After that you can simply play the Serenade of Water to get to Lake Hylia.
HOWEVER: A mini-boss in this next dungeon is really hard unless you have Biggoron's sword. Here is how to get Biggoron's Sword. If you don't feel like going through all that rigmarole to get the blade, Din's Fire is also effective, so maybe bring some green potion so you can use Din's Fire repeatedly.