Instructions
Pull out your ocarina and play the Prelude of Light. This song will warp you back to the Temple of Time.
Enter the temple and go to the pedestal from which you pulled out the Master Sword.
Press the "A" button to put the sword back in its place and go back in time seven years.
Head back to the Temple of Time when you want to go forward in time and press "A" at the pedestal to retrieve the sword.