1) Go to "My Business"-->"Settings"-->"Hours and Scheduling"
2) On that page select "Edit" under "Integrate Calendars"
3) Select whether you want to sync to (import) or from (export) your BookFresh calendar and the calendar you want to sync with (Google, iCal or Outlook)
4) Follow the directions listed.
Please note that events imported to BookFresh from an external calendar and items exported to an external calendar are not editable in the calendar they are imported into. So if you export your BookFresh calendar to a Google calendar you cannot edit the imported events in the Google calendar. Likewise you cannot add appointments to the BookFresh calendar that was imported into your Google calendar.