Denied unemployment, how do I appeal? - 14 months and counting

My claim was denied after 23 weeks of waiting, and the letter says I have a short window to appeal. I do not usually post, so bear with me. 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?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.