When specifying points with the pointer, click the first point and move the pointer to the next point. A preview shows you the placement and size of the entity. When you are satisfied, click the second point.
To specify coordinates, you can click in the graphics area with the pointer or type numbers on the command line in the following formats.
Cartesian 2,2 are X,Y coordinates
Polar 5<45 indicates length 5, angle 45 degrees
Relative @2,2 where @ indicates that the pair is relative to the previous point