According to Moses, who wrote the book, this verse tells us about the sons of Levi, named Gershon, Kohath, and Merari. It explains who Levi's children were, and it helps us learn about the families in the Bible.
Numbers 3:17: And these were the sons of Levi by their names; Gershon, and Kohath, and Merari.
Gives a slightly different order by including Amram as a son of Levi, which could create confusion with Numbers 3:17 if misinterpreted.
1 Chronicles 6:1: The sons of Levi; Gershon, Kohath, and Merari. [Gershon: or, Gershom]