This is the service of the Gershonite clans regarding work and transport:
24. This is the service of the families of the Gershonites. The tasks which He enjoins upon the sons of Gershon, as well as the sons of Merari, are apparently mean and laborious, for it was a hard and also a servile work to carry the curtains and the tabernacle, together with its coverings, the boards, too, and the bars, and the pillars.
We have here the charge of the other two families of the Levites, which, though not so honourable as the first, yet was necessary, and was to be done regularly. 1. The Gershonites were charged with all the drapery of the tabernacle, the curtains, and hangings, and the coverings of badgers' skins, Num 4:22-26.
Commenting on Numbers 4:21-33
At the appointment of Aaron and his sons,.... As they shall order and direct: shall be all the service of the sons of the Gershonites; everyone of them was to take their share, as Aaron and his sons should appoint them: in all their burdens, and in all their service; what each of them should carry, and in what they should perform duty: and ye...