Where Did the Nephites Get their Priesthood Authority?

Host Martin Tanner explains by what Priesthood authority Lehi and his family went to the New World, and there, organized new Churches and Synagogues, and performed Ordinances, including baptism.  If no family of Latter-day Saints can simply decide to move to a new country, and start a new branch or stake, by what authority did Lehi, Nephi and their extensed families form new churches and synagogues in the New World, and perform ordinances there?  In this episode of Religion Today, Martin Tanner answers these questions, and many related ones.