Here’s what 3 Nephi 20–21 might’ve been like.
When He appeared to the Nephites, the Savior shared an overview of Heavenly Father’s entire plan.
He taught them about the purpose of the law of Moses, which was now fulfilled.
He taught them that going forward they should live His gospel and take the sacrament.
He also told them what would happen next—how hundreds of years later, a record of the Nephites would come forth, the gospel would be restored, and Israel would be gathered again.
All of this is happening in our day, just as the Savior said!
PS—You can find all of the Book of Mormon videos here.