(several ways to do this, but here’s one with the STM32CubeProgrammer and Windows)

1. Download the .hex file.
2. Connect the board through the ST-Link USB.
3. Open STM32CubeProgrammer, choose ST-Link and Connect.
4. In Erasing & Programming choose the .hex file path, don’t skip flash erase, and Start Programming.
5. If everything is okay, connect the second USB port. Two devices should be listed (NOD_F767ZI and PYBFLASH).