Click the Object Flow button 
on the diagram toolbar.
On the Diagram, click on the source element.
Drag the link to the destination element.
Drop when the second element is highlighted.
An object flow relationship can be drawn:
To create an object flow link between two elements:
Click the Object Flow button
on the diagram toolbar.
On the Diagram, click on the source element.
Drag the link to the destination element.
Drop when the second element is highlighted.
Related Topics:
Creating Links
Moving Links
Editing Links