In America the Jury decides if someone is Guilty or Innocent after a crime has been committed.
The Lawyer tries to convince the Jury that his client or defendant is innocent.
The Judge is in charge while the trial is going on & hands down a sentence after the Jury has decided if the Defendant is guilty or innocent. You understand now?
When the police write you a speeding ticket, you can go to court instead of paying the fine & they will set a date for you to go to trial.
Then a Jury hears your explanation for getting a ticket & either says " your guilty of speeding or..you're innocent because your car was possessed by a demon & it wasn't your fault..you're innocent".