All will have to be put on hold until I can purchase a Jack Adapter Stereo 3.5mm To 6.35mm for my earplugs/earbuds so that I can hear something.
What the Cubase does, however, recognize is that the mp3 file that I’ve inserted has indeed got sound as the sound frequency levels go up & down exactly as the visual graph says it should, but it is all completely muted… 
The attached jpg shows which file…but it doesn’t matter because there’s still no sound even with the firmware updated. 
But there is another problem, in that, the Steinberg UR242 USB AUDIO INTERFACE I had bought is not working as it should either. I had tested it out with an AKG mic and it seemed to work okay through Audacity, but I’ve just realized that I’d unwittingly had my LifeCam mic switched on at the same time and as it happens it was THIS LifeCam mic that Audacity was actually picking up as I was doing the recording. So the Steinberg UR242 USB AUDIO INTERFACE itself is not functioning at all as it should.
To make the farce even worse—because of the BREAKTHROUGH that we’d had with the Cubase 9.5 LE AI Elements with the shortcut on the desktop plus the GUI working albeit in a limited way—I felt fairly confident, so I went ahead yesterday and bought the Cubase 9 (shop owner said I could update on the net to the 9.5 at no extra cost).
What a nightmare…
Now I’m left seemingly with not only a non-functioning Steinberg UR242 USB AUDIO INTERFACE, but also a Cubase 9.5 LE AI Elements that is for some reason not doing it’s most important job—that is to produce SOUND.
I could just put the Cubase 9 CD in—and hope for the best. 
Anyways, thanks very much for your valuable input. 