This spanning construct is intended to contain the complete flight of stairs from the lowest level to the roof (if applicable). You can create separate constructs for each stair tower, or a single Stairs construct that contains all stairs for the entire project. If you view the properties of the construct on the Project Navigator palette, you will note that all levels are checked. This makes it spanning. To work with this construct, draw a single run of stairs at the lowest level, and add railings and any slabs needed for landings. Then use the Stair Tower Generate tool (on the Design Palette - Design Tool Palette Group) to copy the stairs, railings and slabs (if desired) to the upper levels.
To make the multi-story stair display correctly in view files, use the Medium Detail Intermediate Level display configuration as an external reference (xref) display override when referencing the stair into a view. Select the Medium Detail Intermediate Level display configuration for the intermediate levels, and the Medium Detail Top Level display configuration for the top level stair reference.
The Stairs construct is referenced in the Floor Plans, Composite Model and Section View files.