This can be done using the iCal link that the app provides. You would then subscribe to that link in Google Calendar:
- Navigate to the app's settings > Client Calendars
- On the first active tab (iCal) copy the link that is provided
- Open Google Calendar (https://calendar.google.com)
- Click the button with the three dots next to Add Calendar and select From URL
- Enter the iCal link from the second step (for example https://bobclass.com/ical/courtfour)
- After a few minutes, the appointments will be loaded and visible in Google Calendar.
- You can enable or disable the visibility of this calendar in the left hand side panel in the Other calendars section.
- Note that Google does not sync very frequently; changes may take up to a few hours!