I get it... Let me know if it works. In the meantime I will indeed chase down where to stick a driver file. But usually there is a “readme” or “install” text file included with directions. Once moved over to a Linux folder, Linux will let you read that file even though it is still compressed in the Tar package and not extracted yet. It should tell you where to put it.
Thing is, they keep moving those folders around in different versions. Correct folder, it just might not always be where it was when the directions were written. So some digging around to find that right folder is a normal thing. Wish they would quit that... But MS does it too. :)
Well, I borrowed the USB adapter that works with Linux and then under Kubuntu Device Manager I choose to use the 8812AU adapter that Mint had detected as before and thus works under Linux, but this time I connected Kubuntu via that adapter and so I did not get the "cannot download packages when offline" when I chose to use it (see image in an above post) as instead it it downloaded it. Yet after I disconnected the working adapter there was no adapter and connection to choose.
Back to the drawing board.