Cyber invalid is grateful for any help with capturing You Tube music

First, I have no idea what version of Audacity I have. Not sure how to identify.

Most important for me:

I purchased a DIGITNOW USB AUDIO CAPTURE device from Amazon to get my cassette tapes into an Mp3 format so I can then use the music for exercise. Works great:
= cassette deck output feeds into the Digitnow

= the Digitnow feeds the music to my computer

= once inside the computer, the music is processed by Audacity into an Mp3 forat

My question is this. I would like to get some You Tube music into an Mp3 format via the above instead of downloading onto my computer. Downloading, I learned the hard way, can load your computer with bad stuff. I am hoping that by just “playing back” on You Tube (and not downloading) will avoid the bad stuff getting onto my computer.

My USB audio capture device, Digitnow, has 3 inputs: RCA left; RCA right; standard headphone phone jack. I plugged the headphone jack into the computer; played a You Tube selection, and hoped to record it. Zero signal appears on my Audacity program…which makes my capturing of You Tube music unsuccessful.

Wondering if anyone can tell me what I am doing incorrectly or how to accomplish what I am trying to do?

Many, many thanks

Look at the big bold notice in the pink box near the top of this page.

The recommended way to record audio that is playing on the computer is to use “WASAPI loopback”. See: https://manual.audacityteam.org/man/tutorial_recording_audio_playing_on_the_computer.html