Got a denial letter for unemployment, what now? - 12 weeks in

My claim was denied after 12 weeks of waiting, and the letter says I have a short window to appeal. I have read a lot of threads here and could not find my exact situation. I have not done a hearing before and I am nervous. 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.