The stairs tool can also be used to draw a ramp. A ramp consists of the base, the slope, and the landing.

Ramp Width
This is the overall width of the ramp.
Ramp Height
This is the height of the bottom of the landing. Or, the overall height, not including the thickness of the ramp.
Ramp Length
This is the length of the ramp, not including the base or the landing.
Base Length
This is the length of the base of the ramp.
Landing Length
This is the length of the landing at the top of the ramp.
This is the direction the ramp leads, measured in degrees clockwise from North.
Ramp Slope
This is the slope of the ramp, as determined by the ramp length and ramp height. The base of the ramp may be sloped at a different angle.

To place a ramp, select the stairs tool, check the "ramp" radio button, and hover the mouse over a floor or the ground. If the location is valid, a preview of the ramp will be shown. Left click to place the ramp.