Denied unemployment, how do I appeal? - first time posting

My claim was denied after 12 weeks of waiting, and the letter says I have a short window to appeal. There are 12 people counting on me, so I am trying to be careful. My employer's version of events does not match mine, and I have emails that show it. 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.