ARC
The endpoints of the arc must be either inline horizontal or inline vertical (use the cursor location box in the middle of the toolbar to make sure the second endpoint is inline with the first endpoint).
Move the cursor to one endpoint of the arc, press Enter, then move to the other endpoint and again press Enter, a dialogue box will now appear, input the amount of arc required - if your endpoints are horizontal a minus figure will show an arc below the endpoints but a normal figure will show the arc above if your endpoints are vertical a minus figure will show an arc to the right side of the endpoints but a normal figure will show the arc on the left side

NOTE
If no arc appears, you must get the endpoints horizontal or vertical.

CIRCLE
Press enter on Centre Point of new circle and enter radius in the dialogue box.
You can also draw circles by holding down the left button and dragging to size

ELLIPSE
Move cursor to position of one end of the ellipse then hold down the left button and drag to shape. The line will appear dotted only until you release the left mouse button.