The schedule option enables you to configure the time and the frequency that you want to run jobs. You can configure a schedule for jobs such as backup, restore, inventory, and new catalog. During the job setup, you can choose to run jobs immediately, run once on a specific day and time, or run according to a schedule.
See Scheduling jobs.
When you create a backup selection list, you can set a time range when the resources in the list will be available for backup. The time range is called the availability window. If you schedule a job to run outside of the availability window, the job does not run and Backup Exec displays an Invalid Schedule status for the job on the Job Monitor. When scheduling a job, be sure that the schedule is within the availability window for the resources.
More Information
Setting priority and availability windows for selection lists