To answer this question, we need to look at the definition of the words retribution and restitution.
The word retribution has a vengeful connotation to it and it refers to somebody being punished for a crime that they have committed. For example a murderer will be sent to prison in retribution for his actions.
Restorative justice, on the other hand, refers to giving back something that was lost because of your actions. If you steal money, for example, you could be required to pay the money back. Perhaps a more common example would be paying someone's medical bills if you accidentally ran them over with your car. Restorative justice could also involve compensating them for their loss of income while they are recuperating.