Exodus 29:10

Shall put their hands upon the head of the bullock - By this rite the animal was consecrated to God, and was then proper to be offered in sacrifice. Imposition of hands also signified that they offered the life of this animal as an atonement for their sins, and to redeem their lives from that death which, through their sinfulness, they had deserved. In the case of the sin-offering and trespass-offering, the person who brought the sacrifice placed his hands on the head of the animal between the horns, and confessed his sin over the sin-offering, and his trespass over the trespass-offering, saying, "I have sinned, I have done iniquity; I have trespassed, and have done thus and thus; and do return by repentance before thee, and with this I make atonement." Then the animal was considered as vicariously bearing the sins of the person who brought it - Exodus 29:14

29:10 There must be a sin - offering, to make atonement for them. The law made them priests that had infirmity; and therefore they must first offer for their own sin, before they could make atonement for the people, Heb 7:27,28. They were to put their hand on the head of their sacrifice; confessing that they deserved to die for their own sin, and desiring that the killing of the beast might be accepted as a vicarious satisfaction. It was used as other sin - offerings were; only, whereas the flesh of other sin - offerings was eaten by the priests, in token of the priests taking away the sin of the people, this was appointed to be all burnt without the camp, to signify the imperfection of the legal dispensation, for the sins of the priests themselves could not be taken away by those sacrifices, but they must expect a better high priest, and a better sacrifice.