What is the main conflict in The Settlers by Vilhelm Moberg?

Karl Oskar Nilsson is in the woods near his homestead in the Montana Territory when he hears the sound of an ax. He knows this means that they must have a neighbor settling on a nearby claim and goes to investigate. He finds that it is a man named Petrus Olausson who says his wife and their children will join him as soon as he has a house built. Petrus was exiled from Sweden for his religious beliefs. He is pushy, telling Karl all the things he should be doing differently, but Karl and Kristina are still glad to have neighbors. Karl and Kristina have been settled for several years along with their children. Karl works hard at their farming enterprise and over the early years he has a cow for milk, pigs for meat and the family grows almost everything else they need. Kristina cards wool for spinning and weaving from their sheep and flax.