Hi Hy,

You need to enable enrollment in the Enrollment Settings section of Module Settings. This enables people to enable Enrollment on each event. Once an event is enabled for enrollment, users can register.

If what you are actually after is allowing users to add an event, you need to give the appropriate security group edit access to the module. This will allow them to add and event that needs to be moderated. You can also give them moderator access, in the moderation settings section, which means they can add events and edit others events without moderation.

Cheers
Roger