Select a lateral component from the
Laterals gallery.
Select an existing run of duct to place the lateral on.
Next, use the mouse to slide the lateral to the desired location
on the duct.
The lateral component is attached to the curser allowing
you to moved it back and forth along the duct run.
Left-click to accept the location.
Use to mouse to select a rotation for the lateral.
This selects the side of the duct the lateral will be
connected to.