(Free) Points: Click on a blank area to draw a point. You can move it later.
Lines: Draw a line by clicking on 2 points on the line. You can also create the two points as you go.
Circles: Draw a circle by clicking on its center and then on a point on its boundary. You can also create the two points as you go.
Intersections: To draw an intersection point click on the two objects. If there are two intersection points, the one closer to your last click is chosen.
Deletion: Select an object and click delete or vice versa.
You can drag and drop free points and the display changes dynamically.