Got a denial letter for unemployment, what now? - 16 weeks in

I got a denial letter last week saying I left my job voluntarily, but I was let go as a warehouse supervisor. The letter lists a deadline and a hearing process, but it is hard to follow. Did you bring documents or only talk?

Thanks for writing this out. I went through something close to it 8 months ago, and it settled down once I kept a simple log of every call and form.