To insert a hanger on a pipe, go to
Ribbon: DM Plumbing->3D-BIM-> 
Insert Hanger
Pulldown Menu: DM Plumbing->3D-BIM->Insert Hanger
You will be prompted to select a point on the pipe where a hanger is to be inserted.
Select pipe at location to insert hanger:
A hanger will be inserted at the specified point. The location of other hangers will be adjusted based upon the newly inserted hanger.