Link to download butt:
- download the Latest Version (green button)
- If your mac is older it may not run. In this link, there are older versions too and you can be sure that one of them will be compatible. Start by going to the most recent ones, and always download the .dmg that is for mac os.
- iShowU is the tool that will capture the audio that is being played on your mac.
- Installation tutorial on the link itself, just go down a little bit.