1. What are the different status of an event?

A event has 3 important time points.

Start Time: when the event starts. It is usually the beginning of the first round or first lesson.
End Time: when the event ends. It is usually the ending of the last round of last lessons.
Registration Deadline: when the registration closes. For a tournament, it is usually earlier than the first round. For a group lesson, it is usually earlier than the last lesson.

A event has several important statuses.

Draft: a new created event is Draft by default. A Draft event is invisible to players.
Published: the Organizer publish a Draft event into Published status. A Published event is visible to players and accepts registration.
Registering: a event has one or more registrations. The event state changes from Published to Registering after the first registration.
Registration Closed: Registration Deadline has passed. Players can not register, but Organizer can register a player.
Playing: Start Time has passed. Players can not register, but Organizer can register a player.
Completed: End Time has passed. The event has ended.