If you have installed the drivers. Then it should be detected and in device manager under PORT(COM &LPT) should appear STMicroelectronics Virtual COM Ports (COM*)
If this doesn't appear, then try connecting to another PC USB port or use another cable.
If that appear in device manager, then there is a possibility, that COM3 is in use for another program and it doesn't let configurator to detect your device. Try to change port number via Device Manager -> Right mouse click on STMicroelectronics Virtual COM Ports (COM*) -> Properties -> Port settings -> Advanced... -> COM Port number