John Gill Commentary 2 Chronicles 35:6

"And kill the passover, and sanctify yourselves, and prepare for your brethren, to do according to the word of Jehovah by Moses." — 2 Chronicles 35:6 (ASV)

So kill the passover
In the manner, time, and place, and for the persons it should be killed:

and sanctify yourselves :
by washing themselves and garments, that they might be fit for this service:

and prepare your brethren ;
prepare a lamb for your brethren, or instruct them how to perform their office that needed instruction:

that they may do according to the word of the Lord by the hand of
Moses ;
celebrate the ordinance of the passover in all its rites, according to the law of Moses, at least in every rite in which they were more peculiarly concerned.