Once you have created one or more Jobs, you can check and run them manually by clicking on the Check and Run icons. You may, however, want to schedule Job execution so that you don't have to worry about forgetting or someone being present to run them. One drawback to the Scheduler is that if NPrinting is shut down for any reason, such as a reboot or someone tripping over the power cord, the Scheduler must be restarted manually. A solution to this drawback is running NPrinting as a Windows Service and not using the scheduler (see: How to Configure NPrinting as a Service).
Learn how to set up a schedule for one or more jobs in this tutorial.