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 administrative assistant. I have read a lot of threads here and could not find my exact situation. The letter lists a deadline and a hearing process, but it is hard to follow. Did you bring documents or only talk?

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