when you connect the USB cable, it is recognized by the computer as a USB device and the windows will start installing drivers for it. when you plug the OBD end into the car, the INPA (or other sofware) will recognize that something has connected, reach out, find a car, and you can take it from there...

the main thing is to properly identify the ports, like COM1 or COM3 or whatever... theoretically, the computer should do it automatically, but we all know the windows!!! lol...