Before you start scheduling material constraints with DMS, you have to decide at what level you want to handle material and then the correct job and schedule options must be setup.  Once setup, material constraints can optionally be applied to the schedule run.

There are three levels of scheduling material available in DMS:

1. Job level material handling where the entire job can be delayed if material is not available.
2. Operation level material handling where one or more operations can be delayed if material is not available.
3. Material details level where each material item for the job is detailed and the job and/or operations may be delayed if material is not available.

You can select one or more material handling levels, or use just one material level.  

Also see Scheduling Material Constraints