• Auto-calculate
  number of steps acc. to
  tread-to-riser ratio

Enable this check box if the rise/run ratio is to be optimized automatically based on the tread-to-riser ratio.

• Height difference
  as initial value

When this option is enabled, the rise is defined by the height and the number of rises you specify.

• Rise as
  initial value

When this option is enabled, the height of the stair is defined by the number of rises and the rise you specify.

• Number of rises

Enter the number of rises here.

• Slope

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

Activate 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 Outline Context toolbar.