Parole means letting a prisoner out early if they promise to follow a set of rules about their behaviour.
Whether or not people get parole depends on reports from the staff that have looked after them in prison. There will also be a report from probation staff; these are people who work with newly released prisoners.
It also depends on the type of crime you committed and how stable your home life is. Prisoners who behave badly in prison probably won't get released early.
Six months before the date when they could get parole prisoners are asked if they wish to apply for early release. If they are successful they are let out with a parole licence that contains conditions, which are a set of rules about what you can and can't do.
Once out of prison they must keep in regular touch with home and prison probation officers.