How do one go about preparing & establishing a sub-division for sale off the plan?

I am in the process of getting my sub-division of 3 town houses approved. The town houses are located in Melbourne. I would like to sell them off the plan while tendering for a builder to develop the properties. As I have not sold any of my past developments off the plan, I would like to seek advice as to what is the procedure to get the contractual documentations ready for the properties to sell prior to commencement of construction. Any advices or direct me to the right resources would be most appreciated.

Daniel