And it came to pass that I prayed unto the Lord; and after I had prayed, the winds did cease, and the storm did cease, and there was a great calm.
Equipped with their compass, these ancients appear to have had the advantage of Noah.
Their voyage was toward a "promised land"-- the only name they give it.
They reached it in safety.
Polygamy is a recent feature in the Mormon religion, and was added by Brigham Young after Joseph Smith's death.

Before that, it was regarded as an "abomination." This verse from the Mormon Bible occurs in Chapter II.

of the book of Jacob: For behold, thus saith the Lord, this people begin to wax in iniquity; they understand not the Scriptures; for they seek to excuse themselves in committing whoredoms, because of the things which were written concerning David, and Solomon his son.

Behold, David and Solomon truly had many wives and concubines, which thing was abominable before me, saith the Lord; wherefore, thus saith the Lord, I have led this people forth out of the land of Jerusalem, by the power of mine arm, that I might raise up unto me a righteous branch from the fruit of the loins of Joseph.

Wherefore, I the Lord God, will no suffer that this people shall do like unto them of old.
However, the project failed--or at least the modern Mormon end of it--for Brigham "suffers" it.