Got a denial letter for unemployment, what now?

I got a denial letter last week saying I left my job voluntarily, but I was let go as a project coordinator. I am in Fresno, in case local advice matters. My employer's version of events does not match mine, and I have emails that show it. If you have appealed before, what helped you prepare?

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

Thanks for writing this out. I went through something close to it 4 months ago, and it got easier once I kept a simple log of every call and form.