Not Able to Record computer playback

Heres the situation. Im trying to record a song from youtube with audacity. I recently took a class about audacity on Windows, not mac, but I how to use it and record. Everytime I record, I use my head set. Its supposed to be set up so it records the music in my headphones but it never does. It either records my voice, or nothing at all. Ive own every possible outcome of options could think of. It never works. Am I missing something or is this a common bug. I just need to record my computer’s sound and not my voice.

Macs have no natural ability to record themselves. Haven’t for years. I use the add-on program SoundFlower.

It’s a little convoluted to use, so follow the directions and don’t go by gut instinct.