[Koopaking]

You've got to go to the Goron area and follow the owl to get the Eye of Truth, then use it outside to find the ghost of what's-his-name the Goron, and follow him all the way back to the first area and climb up to his grave. Play the song of Healing for him and you'll get the Goron mask. Transform into the Goron and pull on the stone to reveal hot spring water. Go back to where you got the Eye of Truth and pound in Goron form to open the door to the Goron house and talk to the people there and find the whiny baby. Then you gotta go get some of that spring water, and find the Goron Elder in the second area frozen in ice. He'll teach you the first part of the Goron Lullaby, take that back and play it to the baby with the drums and he'll teach you the rest of it. Then, go back to the first area and use the Goron to roll down the wicked mountain path to reach Snowhead. Play the Goron Lullaby to put the big invisible guy to sleep, and you've made it to the Snowhead Temple. Go through the dungeon and solve puzzles and stuff and fight Goht to win the second boss's remains. THEN GO TO THE NEXT LEVEL.

I remembered all that off the top of my head just now! It might not be exact since I haven't played Majora's Mask in years. If it's the dungeon you're stuck in I can't remember that place step-by-step of course.