Are you trying to Draw a Stringer ? I assume so.....   easiest way is to Draw a Chief Staircase , Open the DBX and set everything the sizes you need eg the 7 3/8 Riser Height , then take a Cross Section through the Staircase , and using the CAD Line Tool copy over the Outline of the Stringer in the Elevation View , once the CAD lines join up, you can Convert the Polyline to a Polyline Solid and apply the thickness (1-1/2"?) and the desired Material  ( eg Treated 2x ) and then Convert i