Appeal deadline questions after an unemployment denial after 4 years as a store manager

My claim was denied after 20 weeks of waiting, and the letter says I have a short window to appeal. 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 saved me later.

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