Appeal deadline questions after an unemployment denial

I got a denial letter last week saying I left my job voluntarily, but I was let go as a teaching assistant. I am in Seattle, in case local advice matters. The letter lists a deadline and a hearing process, but it is hard to follow. Did you bring documents or only talk?

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.