Denied unemployment, how do I appeal? - 7 weeks in

My claim was denied after 7 weeks of waiting, and the letter says I have a short window to appeal. I have been trying to stay organised about it. 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?

Legal aid offices and some workforce centres help with unemployment hearings at no cost. A call is worth it.