These are the descendants of Esau, that is, Edom.
References for Genesis 36:1
Esau married Canaanite women: Adah the daughter of the Hittite Elon; Oholibamah the daughter of Anah son of the Hittite Zibeon,
References for Genesis 36:2
and Basemath the daughter of Ishmael and sister of Nebaioth.
Adah gave birth to Eliphaz for Esau, Basemath gave birth to Reuel,
and Oholibamah gave birth to Jeush, Jalam, and Korah. These are Esau's sons born to him in the land of Canaan.
Esau took his wives, his sons, his daughters, and everyone in his household, and his livestock, all of his animals, and all of the property he had acquired in the land of Canaan; and he moved away from the land of Canaan and from his brother Jacob.
References for Genesis 36:6
They had so many possessions that they couldn't live together. The land where they lived as immigrants couldn't support all of their livestock.