Leviticus 9:5

And they brought [that] which Moses commanded before the
tabernacle of the congregation
That is, Aaron and his sons, and all the children of Israel, as the Targum of Jonathan paraphrases it. All the above sacrifices they brought into the court of the tabernacle to be offered up:

and all the congregation drew near, and stood before the Lord;
that is, the elders of Israel, who were called together, ( Leviticus 9:1 ) , the heads of the tribes who represented the people; as many as well could be admitted into the court no doubt were, to be spectators of Aaron and his sons officiating first in their new office, and to see their own sacrifices offered; and they stood over against where was the symbol of the divine Presence; and the Targum of Jonathan says, they stood with a perfect heart; and no doubt but they were heartily sincere and upright in their sacrifices, as they had been in their donations toward the building the tabernacle, and providing things belonging to it; and they stood with all humility, reverence, and devotion.