Outside, you and Faron will converse shortly. It is mainly just a congratulatory speech.
Anyhow, finish up any other business you have, then use a Bird Statue to return to the sky. Fly to the northwestern corner of the map, into the Thunderhead, and land at the Isle of Songs.
Inside the Thunderhead
Just land on the Isle of Songs and go into the tower - the bridge is already made. Inside, go forward to the circular design and stand on it. Again, use a Skyward Strike to hit the crest across the gap. Afterwards, a scene ensues and you’ll learn the third of the harp songs, Nayru’s Wisdom.
Our next destination is the Lanayru Desert. Exit the tower and dive off of the island. Fly southeast out of the Thunderhead, descending into the yellow beam of light.