I have different services with different durations, for

I have different services with different durations, for example.

Initial Consultation has 30 minutes as the duration
Studio Session has 90 minutes, and a Wedding has 4 hours (trying to get it to 8hours....). When I have a working day from 00:00 to 00:00 (whole day, like my Saturday, when I can work photographing the whole day, I was expecting that if the whole day is available, that I could schedule from any desired available slot, and that the software would block the service duration.

Meaning, if I decided to book a 4 hours wedding starting at 13:00 then it would block from 13:00 to 17:00.

What is happening is that the blocks that I have available to pick from are:

00:00-04:00
04:00-08:00
08:00-12:00 and so forth....

How can I be able to choose an open and long enough slot to accommodate a service with a specic duration?