John,
Rharv gave some good advice and I'm glad you figured out the metronome feature. Like Rharv said, you can keep recording new tracks and just mute the ones you aren't happy with. You may be able to cut pieces of those other tracks later and paste them into another track to make a final track. I do this mostly with my vocals but have also used it with guitar tracks. When you are satisfied with everything, you can go back and delete the other tracks if you need to save space on your hard drive. I like to use Realband when laying down tracks and mixing for the final master.

Del