Communication over USB
Stock firmware registers as "STM32 Virtual COM". Most modern operating systems should work out of the box, but original drivers can be downloaded from STMicroelectronics web page
Firmware is configured to work at 115200 8N1 baud rate
Feel free to use favorite terminal program. For further demonstration will use Terminal App
In some Windows cases Prolific USB to serial controller drivers can claim detected COM port, in this case uninstall driver and install downloaded from ST web page.