Custom Stair Based on a Standard Stair Type
To design a new stair based on a standard type, activate the Stair tool. From the Info box, click Create Stair.
In the appearing dialog box, use the two top buttons to choose whether to build a stair or a slope. If you choose Slope, the symbols of those stair types whose geometry can be transformed into slopes will automatically turn into symbols of slope; all the other buttons become gray.