Appeal deadline questions after an unemployment denial - what worked for you?

My claim was denied after 21 weeks of waiting, and the letter says I have a short window to appeal. I worked as a graphic designer before this. The letter lists a deadline and a hearing process, but it is hard to follow. If you have appealed before, what helped you prepare?

Stay calm and stick to facts. Mine lasted about thirty minutes and felt more like a conversation than a trial.