This parshah was about the first burnt offerings. It went on for seven days. I believe that each day they took down the tabernacle and then put it up again.
Aaron and his sons leaned their full weight on the bull. If the bull moved away they would fall. They were fully engaged in the offering and were fully connected to G_d. Moses was the priest for these seven days. The teacher showed the Kohans how it is done.
By putting the blood on the horns of the altar, they made the altar holy. The blood represents passion. They committed their passions to the offering...and to G_d.