• Number of steps
  based on
  tread-to-riser ratio

Select this check box if you want Allplan to automatically optimize the rise/run ratio based on the tread-to-riser ratio.

• Difference in height
  as a starting value

Select this option if you want to define the rise by the height and the rise number you specify.

• Rise
  as a starting value

Select this option if you want to define the height of the stair by the rise number and the rise you specify.

• Rise number

Enter the number of rises here.

• Rise

Enter the height of the rises here.

• Height at bottom

Enter the TLFF of the bottom of the stair.

• Height at top

Enter the TLFF of the top of the stair.

• Create top step at height of slab

Select this option to create the top step at the height entered for Height (top).
You can achieve the same effect using the Top Step setting on the Stair Geometry Context toolbar.