Converting commercial unit into a residential unit

[John Bianco]

Hello i recently closed on a duplex in Sheboygan,Wi and the property has a commercial garage unit that is 3 stories on the back of the property in the ally way. It was used as a carpet warehouse in the past. My plan is to renovate it and convert it into another rental unit. Does anyone know the steps to go about doing this? or if its even legal?

Thank you!