Numbers 7:1, 10, 84

On the day when Moses had finished setting up the tabernacle and had anointed and consecrated it with all its furnishings and had anointed and consecrated the altar with all its utensils

And the chiefs offered offerings for the dedication of the altar on the day it was anointed; and the chiefs offered their offering before the altar.

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