Draft and Published Modes
According to your needs, your event's website can be in draft mode, which means that it is only visible to the owner of the website; or published, which means that it is accessible to the public.
As the event owner, you can change this status by choosing your option at the top of your organiser's page, next to the event's title.
When in draft mode, the website will be only visible for the owner of the event by clicking on Go to the Event Website.
The message displayed to the public will be 'This page is currently under construction. Please come back later.'