Here you learn the spin attack for your sword and get a magic meter for it. Use a bomb to destroy the rock wall and gain entrance to the Great Fairy Fountain. Once you have climbed the wall, you should find an entrance to Death Mountain Crater on the right, and a conspicuous rock wall on the left, with a sign post and owl in between. You will eventually reach a wall which you are able to climb, but before doing so, kill any Skulltulas clinging to it.
Equip the Hylian Shield and crouch to protect yourself, continuing only when the showers momentarily pause. Soon after the mountain will begin to erupt, and shower you with debris. Use your Bombs to destroy any boulders blocking your way. Find the flagpole nearby Goron City and climb the adjacent slope.
After obtaining Bombs and the Hylian Shield, journey to the mountain's peak. The first Great Fairy Fountain that you are likely to encounter is at the top of Death Mountain. Death Mountain Peak Entrance to the fountain