Now that you have a Building setup, the next step is to create some Floor plans (ie., 1 bedroom or A22, etc). Regardless of your naming convention the idea is that you will create the various floorplans first, and then assign UNITS to each floor plan (see next step).
To add a floor plan GOTO: PROPERTIES --> BUILDINGS --> Select the Building in Question.
Next, click on FLOORPLANS Tab and then the + NEW FLOORPLAN
Complete the Floorplan Information and if you want, the Floorplan Marketing information. Click SAVE to save your newly created floorplan.