Adding an additional property to the back lot of my duplex

[Ian Russell]

I have a duplex that sits on a big lot and I spoke with the county today and they said that I can build a property with a maximum of 11 units.  This is an area that I dont have any knowledge in.  They told me my first step is to get it approved which I need to fill out an application and go to a meeting to get approved.   Would my first step be to contact a builder and get the exact costs on how much it would cost to build a duplex/4 plex or what ever I decide?  I know they need to have a plan when I go to the meeting so Im assuming I would have to hire a builder to draw up the plans.  Any advice would help.  I am sure its pretty complicated but seems like something I should do 

thanks

Ian