Building on land with current structure

[Cindy M.]

An investor friend owns 10 acres of land in CA. The land is zoned for 4 units per acre. Currently, there is only one home on the property-2bed/1bath, with utilities all pulled to the house. We’ve discussed a long term goal of putting 39 other units on the property and renting them out. We’re open to all structure options. Being novices to land building, we’re timid in moving forward. Does anyone have any advice/recommendation on type of structure to build/stay away from?