What is the significance of the laying on of hands?
Leviticus 4:4 (ESV)
4He shall bring the bull to the entrance of the tent of meeting before the LORD and lay his hand on the head of the bull and kill the bull before the LORD.
As with the burnt offering, the worshipper (in this case, the priest) brought his offering to the tent of meeting. There he placed his hand upon the animal and slaughtered it. See commentary on Leviticus 1:4.
4 He shall bring the bull to the entrance of the tent of meeting before the LORD and lay his hand on the head of the bull and kill the bull before the LORD.