Got a denial letter for unemployment, what now?

I got a denial letter last week saying I left my job voluntarily, but I was let go as a production planner. It has been a long 12 weeks. The letter lists a deadline and a hearing process, but it is hard to follow. If you have appealed before, what helped you prepare?

Stay calm and stick to facts. Mine lasted about thirty minutes and felt more like a conversation than a trial.

File the appeal before the deadline, even if you are unsure. You can gather documents afterwards. That is the one part I would not wait on.