steps and cost of building quadplex

[Zaid Badabwan]

Hello friends

I intend to add quadplex to an existing one in Tampa, Florida, and talked to the county to confirm zoning. I would appreciate your expertise on the steps I should take. Do I start by hiring an engineer to make the design and get county approval and permits, or securing the building loan first. Any advice will be welcomed. I know that your real life experience will be more valuable than anything written in official sites. I am also sure that your knowledge and experience will also save me in preparation and building cost. Thank you all, I have asked questions before and received very precious answers from you.