To create an L shaped stair

Select the Stair Maker tool.
The Stair Maker dialog opens.
From the Configuration menu, choose the second icon from the top representing an L shaped stair.
The Stair Maker dialog displays the specific fields for creating an L shaped stair.
(Optional) Select a family from the Family combo box. The first part belonging to the selected family displays in the Part field, along with a description to the right of the Family field.
(Optional) Select a part from the Part option menu.
From the Type option menu, choose Closed or Open.
Set the Level to either Default or Active.
Set the Symbology for the form.
Set the measurements of each feature of stairs in the fields to the left of the Preview window.
Click Place.
The Place Compound Cell dialog opens.
Turn off Clockwise to create a counterclockwise walking line.