By connecting points of elementary objects or curves, you can construct line graph and polygon. You can also construct horizontal and vertical lines, that is, perpendicular line to x-axis or y-axis.
"Connect points" mode
Click the button "Connect Points" on the Tool Bar of the Data Panel .
Now, the cursor on the Graph window is in the mode of "Cconnect points".
To cancel this mode, reclick this button, or click one of the "Zoom in" button, the "Zoom out" button, or the "Move" button in the Graph window.
Dragging by mouse
When putting the cursor at the center of a circle or on a point, the cursor changes to the pencil form.
Then, left click and drag to another object (point, coordinate axes, or elementary object). When the point color is changed, drop there.