en_tn/1ch/23/30.md

They also stood

"The Levites also stood at the temple"

whenever burnt offerings were offered to Yahweh

This can be stated in active form. AT: "whenever the priests offered burnt offerings to Yahweh" (See: rc://en/ta/man/translate/figs-activepassive)

new moon festivals

These holidays marked the beginning of each new month.

A fixed number, assigned by decree, always had to be present before Yahweh

"A specific number of the Levites were always assigned to be present at the temple to make offerings to Yahweh"