Albert Barnes Commentary Exodus 40:23-29

"And he set the bread in order upon it before Jehovah; as Jehovah commanded Moses. And he put the candlestick in the tent of meeting, over against the table, on the side of the tabernacle southward. And he lighted the lamps before Jehovah; as Jehovah commanded Moses. And he put the golden altar in the tent of meeting before the veil: and he burnt thereon incense of sweet spices; as Jehovah commanded Moses. And he put the screen of the door to the tabernacle. And he set the altar of burnt-offering at the door of the tabernacle of the tent of meeting, and offered upon it the burnt-offering and the meal-offering; as Jehovah commanded Moses." — Exodus 40:23-29 (ASV)

Moses performed these priestly functions (Exodus 28:1 note), before the holy things with which they were performed were anointed. The things had been made expressly for the service of Yahweh, by His command, and in this fact lay their essential sanctity, of which the anointing was only the seal and symbol. Aaron and his sons, on similar ground, having had the divine call, took part in the service of the sanctuary as soon as the work was completed (Exodus 40:31). But Moses took part with them, and most likely took the lead, until they were consecrated and invested (Leviticus 8) and publicly set apart for the office.

Before the veil — That is, opposite the ark, in the middle between the table of showbread on the North and the candlestick on the South (Exodus 40:26).