Got a denial letter for unemployment, what now? - 6 months and counting

I got a denial letter last week saying I left my job voluntarily, but I was let go as a procurement assistant. I do not usually post, so bear with me. The letter lists a deadline and a hearing process, but it is hard to follow. If you have appealed before, what helped you prepare?

I printed my emails in order and wrote a one-page timeline. The hearing officer kept going back to it.