First, get the scarecrow song as a kid. To do this, go to Lake Hylia as a kid through Zora's Domain and speak with the scarecrow on the shore. Take out your ocarina and he'll want to play. Play any song you make up and that will be your song--don't forget it! Next, you'll need the Longshot. To get this, defeat Dark Link in the Water Temple. Then, as an adult, go to the scarecrows and play the song for the first one. Piere will now appear wherever there is a green Navi but nothing there. Now, when the sun is rising, shoot the sun with an arrow by the Water warp point (with the Water Medalion on it). When the Fire arrows appear, go down the hill but don't drop-- just go to the edge. Play the scarecrow song to make Piere appear, then use the Longshot to hook on and grab the arrows.