Audacity does not record directly to MP3. It records in lossless PCM then you can export to MP3 if you add LAME ( FAQ:Installation, Startup and Plugins - Audacity Manual ) to your computer.
The link I gave you already does that. Take your computer mouse and click on this blue text: Tutorial - Recording Computer Playback on Windows - Audacity Manual.
If you need it translated to steps that you can follow, perform these steps:
- In Audacity, open Device Toolbar.
- In the first (Host) box of Device Toolbar, choose “Windows WASAPI”.
- In the second (Recording Device) box, choose the (loopback) input for the device you are using for playback. For example, if you are using “Speakers” for listening to playback, choose “Speakers (loopback)” in this step.
- In the third (Recording Channels) box, choose mono or stereo.
- In the fourth (Playback Device) box, choose the Speakers or Headphones that you are using for listening.
- Start playing the audio you want to record.
- Press the big red Record button in Audacity.
Of course, we assume you have copyright holders’ permission to make these recordings.
Gale