Crown prosecutor would start by describing the circumstances around the incident, he/she might also call on the police officer who ticketed you as witness. You then would have your chance to tell your case to the judge. If you have witness in your favor you could call on the witness as well. You would also get a chance to cross-examine the crown's witness.
If you lose your case, you could bargain down the penalty in court or ask to pay the penalty using a payment schedule.