Morning Sky claims his knowledge comes from family oral traditions, including a story about his grandfather helping rescue a being from a crashed UFO in the New Mexican desert in 1947. He also alleges that the Hopi people were contacted by extraterrestrials, who taught them the secrets of the universe before the rest of the world. His views have been met with skepticism, including by the Hopi tribe themselves, who have stated that they do not have members with names like "Morning Sky". A 1992 article in "The Skeptic" magazine describes his presentations as entertaining but containing highly discredited UFO claims.
This is his core text, and your best starting point. Finding it for free requires some persistence: la transcript by robert morning sky free