Built-In mic recording

Instead of firing up the studio computers, I decided to use the Mac pro book with wave labs to record a couple of test acoustic tracks in montage, using the built-in microphone this morning. However, all that does is create an audio loop. From what I can tell, there is no way to do multitrack recording, using the built-in microphone without running into this audio looping problem. I can record individual guitar tracks in the audio section but in order to listen to the metronome and the other guitar at the same time, I have to do it in the montage section that’s creating the audio loop.
Does anybody know how to do this?

Solved… use headphones.