This is a very alpha-tested feature that will only work with a theme customized to use it. What it allows you to do is to create an event that has defined attributes (Event name, time, location, etc) that can displayed on the page and used by the theme in a structured format. For instance, you could have a calendar-style listing or have the event page automatically show that the event has passed.
If events are central to what you do and you are interested in customizing your theme to use this feature, please drop us a note at info@outpost.pub.
Image Credit: NASA