I've not been to one, so I can't tell you exactly what to do, but it really just means that you got selected randomly from a pool of residents in the area to hear a case. They're just going to screen you to seem if you are impartial. (Meaning, if you REALLY don't want to do it, you'll need to seem biased.) However failure to show may be seen as in contempt of court, which is not good. (It may lead to an order for arrest.)
-dunno001
-On a quest for the truly perfect game; I don't think it exists...