In the shown position the Tavern covers all Citizen houses, while in the top position it misses one. The position of the Tavern and the Fire station are interchangeable depending on the particular needs of your settlement. The Citizen tier unlocks the first Support Buildings, as well as the Tavern and the Alms house. When additional Construction area is created (either by another Marketplace, or by Market buildings) these roads can be placed and the Peasant houses will be connected. The roads that connect these to the Marketplace fall outside of the Construction area provided by the Marketplace. It is designed to minimise the number of houses that need to be demolished when adding Needs buildings later on, hence the strange layout near the Marketplace.
Shown here is a base layout for Peasant housing. Layouts can easily be created and edited using AnnoDesigner, and you are encouraged to take these base layouts and make them your own. Note that there is no universally correct layout, and the exact placement is often up to preference. This page shows off some housing layouts that are easy to expand to higher civilisation levels.
However, once additional Needs and Support buildings become available it can be hard to efficiently place them in the grid. It's easy to create long columns of houses around the Marketplace when starting off with a settlement.
