This tool gives you a way to place a point on the canvas anywhere along the line of a curve. The point will not be connected to the curve in any way.
Select the curve to follow.
You can move the point along the curve to locate your final position.
There is a slider at the top that will move the point up and down the curve. Move the slider and release it to see the exact placement.
From Start / End
You can designate the precise placement from the start point or the end point of the curve. Fill in a value in either box.
The point will be created as a stand-alone key point. It is not associated with the curve, it just happens to rest along it's shape.