By default, your resource is calendar is private. Customers can book a private resource, but the calendar events will only be visible to you, unless you explicitly mark them public.
Visibility ensures that if you publish a calendar, it will be visible based on your setting.
If you want to make your resource calendar Public, change calendar settings in Resource configuration to Public. When customer looks for the availability, they will be able to browse you entire calendar vs selecting individual dates.
To display resource booking details like subject and notes on public calendar, choose Public with Subject & Notes option.