Fellowship offering should be a male or female animal without defect. The priest have to sprinkle the blood on the altar and fire is set on the altar to burn the cut pieces of the animal. The aroma from the burning is pleasing to God. All fats from animals belongs to God. We are not to eat any fat or blood.
God told Moses that sin offering was for people who had intentionally sinned against God or when an anointed priest sins and brings guilt on the people. A young bull is to be killed for sin offering.
God hold the person who knows the truth but refuses to testify to a public charge responsible for committing a sin. This is equivalent to someone who bears false witness against the neighbor because they know the truth, but intentionally lie against it. A female lamb or goat is required to atone for this sin. If unable to afford a lamb, he can use 2 doves or 2 young pigeons, or fine flour without oil and incense is acceptable for the poorer population. God accommodates the levels of punishment based on income or economic status.
God gives Moses further regulations for burnt, grain, and sin offerings.