Upgrade- Hold mouse over building and press "u". You can move the buildings you build. A church give your population happiness. A house gives you gold and takes food. A quarry gives you stone and takes food. Takes one population. A ship gives you food. Takes one population. A shop gives you a little of everything. Takes one population. A farm give you food but takes gold. A clinic takes food and gold but stops the plague and gives happiness. Apartments will give you population but takes gold.
WARNING- You HAVE to build a house and a quarry in order to progress. The Plague will strike at anytime and kill your population, you can prevent this with a clinic. Please post any suggestions in the comments.