This verse describes a specific step in the ordination ceremony of Aaron and his sons as priests in ancient Israel, as detailed in Leviticus 8. Let's break down the meaning:

"He presented the ram of the burnt offering": This refers to Moses, acting under God's direction, presenting a ram specifically designated as a burnt offering. A burnt offering was a sacrifice where the entire animal (except the skin) was burned on the altar as a pleasing aroma to the Lord. It symbolized atonement for sin and complete dedication to God.

"Aaron and his sons laid their hands on the head of the ram": This act of laying hands on the animal was a crucial symbolic gesture. It represented the transfer of their identity, sins, and dedication onto the animal. In effect, they were identifying themselves with the sacrifice. This symbolic transfer served multiple purposes:

Identification: Laying hands signified that this sacrifice was specifically for them.
Substitution: The ram was offered in their place. The ritual implied that they deserved punishment for their imperfections, but the animal was being accepted by God as a substitute.
Dedication: By identifying with the sacrifice, they were also symbolically dedicating themselves to God's service. They were committing to a life of service and obedience as priests.

In essence, this verse describes a ritualistic act where Aaron and his sons, the soon-to-be priests, acknowledged their sinfulness and dedicated themselves to God by symbolically transferring their identity and commitment onto a ram, which was then offered as a burnt offering. This act was a vital part of their consecration, setting them apart for their sacred duties.

The laying on of hands is a recurring theme in the Bible, often signifying the transfer of blessing, authority, or responsibility. In this case, it's a key element in the process of atonement and dedication required for priests to serve God effectively.