To edit the appearance of a diffuser schedule either before or after it has been placed on the drawing, go to
DM HVAC 
Diffusers Insert Diffuser Schedule
The Diffuser Project Schedule dialog box will open as shown below.
Press Edit Column Labels and Order. The Diffuser Schedule Label Display and Order dialog will appear. Uncheck the box in the Display column for the Description, Model, and Notes rows as shown below. These empty columns previously displayed in the diffuser schedule will not be included.
When you have finished editing the label display and order columns and rows, press OK. You will be returned to the Diffuser Project Schedule dialog box. Press OK. Design Master HVAC will take you to the drawing and ask you to specify an insertion point for the diffuser schedule. Press ENTER to place the new diffuser schedule in the exact same location as the previous location. Design Master HVAC will automatically erase the old diffuser schedule and replace it with the new one. Your drawing should now match the one shown below.
Congratulations! You now know how to perform the basic diffuser functions using Design Master HVAC.
See Ducts for the next tutorial.