Who built the first school for navigation in town of Sagres?

The generally accepted answer is that Prince Henry the Navigator didn't build a school in the modern sense, but he established a center of navigation studies at Sagres. There's no definitive proof of a formal "school" building, but rather a collection of resources and experts that functioned as a center for cartography, astronomy, and nautical science. So while we can't pinpoint a builder of a specific school building, the initiative and the foundational work are attributed to Prince Henry the Navigator.