Aaron was the father of Nadab and Abihu. He was also the father of Eleazar and Ithamar.
Aaron married Elisheba. She was the daughter of Amminadab and the sister of Nahshon. She had Nadab, Abihu, Eleazar and Ithamar by Aaron.
Aaron’s oldest son was Nadab. Aaron’s other sons were Abihu, Eleazar and Ithamar.
They must take care of everything connected with the tent of meeting. When they do, they are acting for all the Israelites.