Seeing as you want to give it a go - it took me a while to figure how to use it. You will see the panel has the usual record, play buttons as you'd expect.
What took me time to work out was the default is 'microphone'. This records whatever sounds the mic picks up, which you don't want.
Change it to 'stereo mixer' (or similar, depending on your pc) and it will record whatever the pc is playing.
Download the 'lame' extension at the same time as you download Audacity, and you can save your recording as mp3