To enable the Booking feature "to attendees only" we need to go first to the profile we want to use, and click on the "edit" button
Then, on the menu that opens up, we scroll down the options and on "Booking" we set the "Allow booking for:" to "attendees" as seen below
After we did our changes, we have to click on "commit" to save them, and now the connection is ready to allow bookings from attendees only

How to do bookings as an attendee

To make a new booking as an attendee first we need to click on the icon of the calendar, in the top right corner of the screen
Then we will get the calendar to select the date:
Select the resource you wish to book:
Select the time frame:
Fill the name for the booking:
After applying the changes you will get a confirmation message:
Below you will see how the page looks, once the booking is saved: