How do I get my Mac to do nothing when I insert a cd?
You can do this in your Mac's system preferences:


Go to Apple > System Preferences > CDs &amp; DVDs
You'll see a menu for When you insert a music CD
Change that menu from "Open iTunes" to "Ignore".


Notes: 


You may also want to check the options for Blank CD and Blank DVD as they also include built-in options to open iTunes. 
The other menus also provide the ability to run a script, so if you got the MacBook from someone and you're using their old account, these may be worth checking as well in case they're launching iTunes or another application.