Temple of Time
Go to the Temple of Time and play the Song of Time in front of the altar to
open the door. Enter the next room and take the Master Sword. You'll be
warped ahead 7 years in time, and you'll meet Sheik and Rauru, the Sage of
Light. Sheik and Sage Rauru will tell you to go to Kakariko Village, so leave
the temple of head on over there.