What does 1 Chronicles 8:39 mean?

The sons of Azel's brother Eshek were Ulam, his firstborn, then Jeush, and Eliphelet. 1 Chronicles 8:39 - Modern Text Bible

(Eshek, Azel's brother, also had sons. Ulam is noted as the oldest, followed by Jeush and Eliphelet. This continues the detailed record of the family.)