Numbers 7:1, 10, 84

On the day that Moses had finished setting up the tabernacle and had anointed and consecrated it and all its furniture, and the altar and all its utensils; he also anointed them and consecrated them [for holy use].

The leaders offered the dedication sacrifices for the altar on the day that it was anointed; and they offered their sacrifice before the altar.

This was the dedication offering for the altar from the leaders of Israel on the day when it was anointed: twelve dishes of silver, twelve silver basins, twelve golden bowls