These are Jacob's wives: Rachel and Leah, Bilhah and Zilpah.
Joseph and Benjamin were Rachel's sons; Reuben and Simeon and Judah were Leah's sons.
The brothers were shepherds. The lad, Joseph, was shepherding the sheep in the field with his brothers, the sons of Bilhah and the sons of Zilpah.
Jacob was not in the field; He remained (dwelled) in the house.
Joseph told his father what his brothers did in the field.
(If) his brothers did a good thing, he told the good thing to his father.
(If) his brothers did a bad thing, Joseph told his father the bad thing.
Joseph's brothers did not tell Jacob a thing about Joseph.