Denied unemployment, how do I appeal?

I got a denial letter last week saying I left my job voluntarily, but I was let go as an accounts payable clerk. Any experience at all would help. The letter lists a deadline and a hearing process, but it is hard to follow. If you have appealed before, what helped you prepare?

Keep everything in writing and save the confirmation numbers. It saved me later.

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