Got a denial letter for unemployment, what now? after 12 years as a retail manager

My claim was denied after 16 weeks of waiting, and the letter says I have a short window to appeal. 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.