What will my preliminary hearing entail?

This sounds like a Disorderly Conduct charge. It is a violation and not a crime. If you were given an appearance ticket and this will be your first day in court, it is an arraignment. You could plead not guillty and perhaps get a lawyer to negotiate a disposition. The District Attorney might make an offer when you are in court. I am guessing that it could possibly be a fine in the range of $200 to $400. The maximum penalty is 15 days in jail.