Got a denial letter for unemployment, what now? after 18 years as an accounts payable clerk

I was told my separation was for misconduct, which is not what happened. It has been weighing on me all week. The letter lists a deadline and a hearing process, but it is hard to follow. 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.