Appeal deadline questions after an unemployment denial, IT help-desk technician here

I got a denial letter last week saying I left my job voluntarily, but I was let go as an IT help-desk technician. I worked as an IT help-desk technician before this. 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.

Thanks for writing this out. I went through something close to it 5 months ago, and it got easier once I kept a simple log of every call and form.