I bought this thing and it installed Audacity on my machine. I put a cassette in and pushed the play button on the outboard device and although the software screen control panel is open on my desktop I can’t hear anything and the software is staying at zeros across the board.
Have a good read of this tutorial set from the manual - it should help you: http://manual.audacityteam.org/o/man/tutorial_copying_tapes_lps_or_minidiscs_to_cd.html
WC
There is nothing in this tutorial concerning this matter
A couple of quick things -
Click Audio Setup in Audacity and select the USB device as your recording and select your regular speakers/soundcard as the playback device.
Navigate to preferences and enable Software Playthrough so you can hear what you are recording.
FYI - Those “cheap little” USB cassette players have a rather bad reputation. Apparently, some of them just don’t work. 
(It’s not a “compatibility problem”. All of them work… or are supposed to work… with the standard Microsoft-supplied drivers.)