Denied unemployment, how do I appeal? (Chicago)

I got a denial letter last week saying I left my job voluntarily, but I was let go as an accountant. I do not usually post, so bear with me. I have not done a hearing before and I am nervous. 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.

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.