Their relatives the Levites were assigned to all the service of the tabernacle, God's temple.
References for 1 Chronicles 6:48
But Aaron and his sons did all the work of the most holy place. They presented the offerings on the altar of burnt offerings and on the altar of incense to make atonement for Israel according to all that Moses the servant of God had commanded.
These are Aaron's sons: his son Eleazar, his son Phinehas, his son Abishua,
his son Bukki, his son Uzzi, his son Zerahiah,
his son Meraioth, his son Amariah, his son Ahitub,
his son Zadok, and his son Ahimaaz.