Whenever burnt offerings were presented to the LORD on the Sabbaths, New Moons, and appointed feasts, they were to serve regularly before the LORD in the numbers prescribed for them.
KJV
And to offer all burnt sacrifices unto the LORD in the sabbaths, in the new moons, and on the set feasts, by number, according to the order commanded unto them, continually before the LORD:
ASV
and to offer all burnt-offerings unto Jehovah, on the sabbaths, on the new moons, and on the set feasts, in number according to the ordinance concerning them, continually before Jehovah;
So the Levites were to carry out the responsibilities for the Tent of Meeting and the Holy Place, and, under their brothers the descendants of Aaron, the service of the house of the LORD.
KJV
And that they should keep the charge of the tabernacle of the congregation, and the charge of the holy [place], and the charge of the sons of Aaron their brethren, in the service of the house of the LORD.
ASV
and that they should keep the charge of the tent of meeting, and the charge of the holy place, and the charge of the sons of Aaron their brethren, for the service of the house of Jehovah.