Appeal deadline questions after an unemployment denial after 11 years as an operations analyst

I got a denial letter last week saying I left my job voluntarily, but I was let go as an operations analyst. I do not usually post, so bear with me. The letter lists a deadline and a hearing process, but it is hard to follow.

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.