Those who went with Nephi were called Nephites, and those who remained with Laman became Lamanites.
The Nephites built houses, planted fields, and lived as civilized people, and the Lord often revealed his will to them through prophets and holy men.
The Lamanites became lazy, lived in tents in the forests, and killed wild animals for their food.

Their skins also became dark.
The greater part of the Book of Mormon is about these two peoples, their wars with each other, etc.

The Nephites ought to have remained a good people, because the Lord blessed them so much: yet they often did wrong.
The Lord would prosper them until they became rich; then they would become proud and at last wicked.

Then the Lord would allow the Lamanites to come upon them, and there would be bloody wars.

So the story goes for hundreds of years.
Both nations became very large and occupied the greater part of North and South America.
At times the Lord would raise up prophets who would preach to the wicked.
Usually these teachers were Nephites, but sometimes they were Lamanites.
Sometimes great numbers of Lamanites were converted to the Lord, and when they once accepted the truth, they did not fall away so easily as their Nephite brethren.