About including weekends
For certain tasks, you might need to schedule work to proceed on weekends. For example, print shops often work 24 hours a day, 7 days a week, so if you have tasks that go to a print shop, you can have these tasks take into account weekend days.
For example, you have a task called "Print Brochures at print shop." This task might start on Friday 6/15, and have a duration of three days. If you choose to include weekends for this task, its end date is end of business Monday, 6/18. If you choose not to include weekends for the task, it ends on end of business Wednesday, 6/20.