Denied unemployment, how do I appeal?

I got a denial letter last week saying I left my job voluntarily, but I was let go as an accountant. I worked as an accountant before this. The letter lists a deadline and a hearing process, but it is hard to follow. 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.

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