Got a denial letter for unemployment, what now? after 6 years as a janitorial supervisor

I got a denial letter last week saying I left my job voluntarily, but I was let go as a janitorial supervisor. I have not done a hearing before and I am nervous. 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.