I've installed WPLSoft, but it didn't asked any hardware device to be present and attached to my PC. I've accessed the only menu that appears to be available and that's the Communication one. You need to use that menu to connect to the device in different modes: RS232, Ethernet, USB, CDC, etc.
After installation, go to Help > WPLSoft User Index to read about more the way the software works and how you need to configure it.