You should know that you can also add in available time for Service-based appointments by adding to or modifying your staff availability and/or location availability. The Time screen, however, is the only place where you can customize how your appointment start times display.
If you navigate to Settings → Time, you will see that you have a number of things available to you including the Time Panel Settings, Add Staff Availability, Service Time Display, Class Time Display, and the current Staff Availability Table:
Here's a brief description of what each of them do as well as some helpful links to learn more:
Time Panel Settings:this window has a number of settings to determine how your appointment availability displays to client on the Time panel of the scheduling flow. Learn more
Service Time Display: This window holds the configuration settings for how appointment times display on the Time panel of the scheduler when clients are booking a service-based appointment with you.
Class Time Display: This window allows you to adjust some of the configuration settings that affect how class sessions display on the "Time" panel of your scheduler.
Current Staff Availability table: This shows you what date ranges you currently have set up on your staff profile and what days of the week are included in those date ranges. Click the blue "View & Edit" button next to it to look at the specific hours your available on those days within the staff profile or click the red "Remove Availability" to complete remove that date range of availability from your schedule.
Preview Scheduler button: as with almost all of the pages in the Settings menu, you can quickly access you mini website and check out changes you made by clicking the "Preview Scheduler" button in the top right