What does Leviticus 5:16 mean?

They also have to pay back whatever they took, plus an extra fifth, and give it to the priest. The priest will use the ram to make things right for them, and they'll be forgiven. Leviticus 5:16 - Modern Text Bible

(Restitution is required: pay back what was taken, add 20%, and then the priest will handle the offering for forgiveness.)