When you create your event you have the option to make it your event Private instead of publicy available (searchable on Billetto and search engines like Google/Bing). Private events are only found through direct sharing or links.
You can make your event private by unchecking the "Public" tick box in the event creator.
You can also choose to save your event as a draft rather than publish it if you're not ready to show the event to the world. You can click Save at the bottom of the page next to Publish and it'll be available as a "Draft" in "My Events".
When you're ready to bring your event to life, visit the My Events page and click on Edit on the draft, make your changes and press Publish