Denied unemployment, how do I appeal?

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. 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?

I printed my emails in order and wrote a one-page timeline. The hearing officer kept going back to it.

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