Denied unemployment, how do I appeal? - first time posting

I got a denial letter last week saying I left my job voluntarily, but I was let go as a barista. I am in Tucson, in case local advice matters. The letter lists a deadline and a hearing process, but it is hard to follow. If you have appealed before, what helped you prepare?

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.