Lesson 43 covers Mormon 1-6. Mormon 6:6 explains how Mormon buried the Nephite records in Cumorah.
The Book of Mormon is the keystone of our religion, and Cumorah is the keystone to Book of Mormon geography. It is the touchstone between ancient and modern times. It is the pin in the map that the Lord gave us so we would not be left in confusion about where the Book of Mormon events took place.
And yet, there is a strong movement among LDS scholars and educators to put Cumorah anywhere but New York.
If you’re teaching or studying the Book of Mormon and you discuss Cumorah, you need to know that many LDS scholars believe the New York Cumorah is the product of a false traditions started in the early days of the Church by unknown people. These scholars teach that Joseph Smith adopted this false tradition and perpetuated it, along with Oliver Cowdery and many others.
I discussed this here: http://mormonmesomania.blogspot.com/2016/11/scholars-prophets-keep-getting-it-wrong.html
Every gospel doctrine teacher in the Church should be aware of what is going on. I hope every one of you rejects the people on the right side of the table and follows and teaches the same things as the people on the left side of that table.
Source: 2016 Gospel Doctrine Resource