Recording Audio from Computer

I have a DJ/Mix set up on my computer and I want to record myself mixing on Audacity.

The only inputs I can find are microphones?
How can I record the audio that is playing on my computer?

Can’t seem to find how to add inputs to the program?
Wouldn’t I add the soundcard?

Thanks in advance!

To record audio that is playing on your computer, see:

Unfortunately there are reports on this forum that suggest that some DJ software prevents this from working and only allow recording using their (commercial) software.