Unlike daycare and overnight stay booking, service bookings need to be created from the calendar.
As services have an undefined length, the calendar makes it easier to manage these.
To create a service booking go to the calendar and switch to the Day or week view.
Then click and drag on the calendar the hours you want to use for the booking.
After this a popup will be shown where you can fill in the details of the booking.
Below is a video showing the process: