How do you get the third fairy in Zelda phantom hourglass?

The third pure metal is in the isle of ruins. When you finally get to the big golden pyramid, beat the temple , go to the boss room ( by then you will have hammer ) . Then you will see the boss (big rock guy, I forget his name). To kill him, step on the hammer switches to send yourself in the air.Then you will automatically turn to arrow mode so you can shoot his weak spots (the red buttons) until he has no rock left and he's only wood. REPEAT THE PREVIOUS TASKS. Then only his head will be left. Continue using the switches to jump on his head and attack that ... Thing! on his head . Repeat until he's dead and go get the metal!!!