Hi Dave,
Create the custom calendar (Tools>Change Working Time> New).
You will also want to make sure that the definition of hours per day and
hours per week matches the calendar you created and change the default start
and end times in the Tool>Options calendar tab.
Apply the custom calendar to the project in Project>Project Information in
the calendar drop-down.
Change the Gantt chart to display the nonworking time from the custom
calendar. Format>Timescale and select the custom calendar from the Nonworking
time tab.
If you have created resources, check the Resource Sheet and change the Base
Calendar for the resources to the custom calendar as necessary.
Tasks without Task calendars will use the custom calendar for scheduling.
Hope this helps. Let us know how you get along.
Julie