en_tn/2ch/35/16.md

the entire service of Yahweh was carried out

This refers to everything associated with the preparation, the sacrifice, and the worship of Yahweh during the Passover. The word "service" can be expressed as a verb and this can be stated in active form. AT: "they did everything that needed to be done to serve Yahweh" (See: rc://en/ta/man/translate/figs-abstractnouns and rc://en/ta/man/translate/figs-activepassive)

kept the Passover

This is an idiom. AT: "observed the Passover" or "celebrated the Passover" (See: rc://en/ta/man/translate/figs-idiom)

then the Festival of Unleavened Bread

This refers to celebrating the festival. AT: "then kept the Festival of Unleavened Bread" or "then celebrated the Festival of Unleavened Bread" (See: rc://en/ta/man/translate/figs-ellipsis)