Give Centre Point:
Select the centre point of the circle using any of the snaps and input options.
After selecting the point a dynamic line is drawn from it to the cursor. This line is defining the radius of the circle and a dynamic circle is drawn around the centre point through the cursor position allowing you to visualise the size of the circle. The prompt now reads:
Give Radius Point:
Select a point on the circle circumference using any of the snaps and input options. The circle is now drawn.
The 'circle' is stored on the drawing as an arc and is edited as an arc. See Modifying/Moving an Arc.