In Both Sonar Producer , Studio and Home Studio
you choose Burn Audio CD from the "Tools" Menu.

Make sure when you "Bounce to Track" or "Export Audio Mixdown" you pay careful attention to "WHERE" you save it
e.g. Create a Folder on your Audio Drive called "Mixes" or similar, and ALWAYS save Mixes to that folder.

Click the "ADD TRACK" button and select the mix you want.
Make sure the "TARGET Drive" is your Optical CD RW/ DVD Drive.
Then press the "Burn CD" Button.