Appeal deadline questions after an unemployment denial - first time posting

I got a denial letter last week saying I left my job voluntarily, but I was let go as an IT help-desk technician. This is my first time dealing with any of this. I have not done a hearing before and I am nervous. If you have appealed before, what helped you prepare?

Keep everything in writing and save the confirmation numbers. It saved me later.

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