A jury is a group of people who have been selected to observe a trial in a court of law. A jury may be called for either a criminal or civil trial, or a Coroner's inquest.
The role of a juror is important because your unbiased opinion is critical to the accused receiving a fair trial.
You do not need to know anything about the law to serve on a jury. The judge will explain the law and any legal terms used to help you fairly consider the matter being heard in court.