More often than not, buildings in nSide will have multiple floors. In the map, the main floor will always be the default view. However, switching between floors or maps can be done in the drop-down menu on left and near the top.
Change the active map or floor for viewing:
Click on the Maps: drop down.
A drop-down box will show the available floors in the building.
Select the floor or level under the top section.
*If your school only has one level, only one map is available for viewing. If your school has multiple levels, individual maps of each floor will be available.