Denied unemployment, how do I appeal? - any advice?

My claim was denied after 13 weeks of waiting, and the letter says I have a short window to appeal. I worked as a production planner before this. My employer's version of events does not match mine, and I have emails that show it. 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.