Assigning a person to an event means that they will receive notifications about this event. You can assign staff by position group or select each person individually. If this event is something you only need bartenders to know about, choose just the bartender group. If this is a business-wide event, choose all employees. If you just need night-shift people to know, select them individually. Once you have assigned employees to an event, you can send reminders to them as the date gets closer.