After you've set up your availability and services, you may want to allow some services only at specific times, like on the hour or at certain time gaps.
1. Go to 'Settings > Services'
2. Select the service you would like to edit
3. Scroll to the 'show more' button under 'duration and pricing' and click on it
4. Under 'available every' select to show the service's availability whenever there's a time slot (e.g. a 30-minute service appears whenever there's a 30-minute gap) or choose a custom duration like every hour.