Once you have set up your Availability and Services, you may want to set certain services to only be available on the hour, or some other specific time interval.
To do this, got to "Settings - Services" and select the service you would like to edit. Scroll to the "show more" button under duration and pricing, and click on it.
Under "available every", you can select the have the availability for that service show up every time there is time available (e.g. if the service is a 30 minute consultation, it will show up where ever there is a 30 minute gap in your calendar) or you can select a custom duration, such as every hour.