Denied unemployment, how do I appeal? (Austin)

I got a denial letter last week saying I left my job voluntarily, but I was let go as a bookkeeper. It has been weighing on me all week. 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 made the follow-up calls so much easier.