Hello,
the STM32F746 contains a RTC hardware (real time clock) which has to be set in order to provide the "real time". The BezierClock example is reading the current time provided by the RTC. During start or the application, the RTC is initialized with a default value, but there is no access to a time server. You can set the RTC directly within the example.
Does this answer your question?
Best regards,
Manfred.