When starting a new project, you should always define your Building Location settings prior to drawing. These settings determine where elements will be placed and how the building will be constructed.
When you define building locations, you are basically doing the following:

1. Defining the levels and stories that your building will have
2. Setting the wall height for each level in your model
3. Specifying where each floor is positioned relative to the ground
4. Selecting the default framing options for each location.