Got a denial letter for unemployment, what now? (Cincinnati)

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

File the appeal before the deadline, even if you are unsure. You can gather documents afterwards. That is the one part I would not wait on.