Got a denial letter for unemployment, what now?

My claim was denied after 10 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. 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.

Keep everything in writing and save the confirmation numbers. It saved me later.