Just land on the isle 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.