OpenDental doesn't have the specific concept of ‘Office Hours’ --- Office Hours are handled together with the Practitioner Schedules in its settings.
For the guide on how to manage Practitioners' Schedules (their Office Hours) in OpenDental, click this link instead: https://intercom.help/carecru/en/articles/3172160-open-dental-how-to-check-practitioner-schedules
Please note:
OpenDental does NOT sync your Office's Weekly Schedule to CareCru due to the way it was designed (it doesn't have a separate area that handles just the Office's Weekly Schedule Hours; it combines them with the Practitioner Schedules).
Hence, you'll need to manually set up your 'Default Weekly Schedule' in the 'Office Hours' settings area in CareCru. Click this link: https://intercom.help/carecru/en/articles/3131120-carecru-how-to-manually-setup-office-hours-if-sync-not-supported