To create a new Event Type, go to Menu > Event Types and click on Add Event Type. A new Event Type page will open up. Fill in all the data that is typical of all the events of this type.
Note that event types also get listed in the Catalog section of the site. And, people can request different dates for an event type than what might be offered. Those requests are emailed to the Event Type Organizers. So, you may want to specify who those organizers are.