Left Buttons
On the far left side of the bar are four buttons that will help you create and edit tracks.
Create New Track adds a new track to the window. A window will appear asking you to choose and/or edit the instrument that you want to use.
Get Track Info - Select the track whose information you want to display/change by clicking in the main track box (where the instrument is displayed), click on the Track Info button, and the same window that allowed you to create the track will appear.
Open Loop Browser opens a searchable collection of GarageBand's pre-made loops at the bottom of the window. Much more about these in the Using Loops section.
Open Track Editor - Select the track that you want to edit, click on the Track Editor button, and an area in which you can edit your tracks will appear at the base of the window.
For much more about creating and editing tracks, see the GarageBand 2.0 - Recording, Editing, & Mixing tutorial.
Watch the video
Part 2.2: Left Buttons
dial-up | broadband
Flash movie
Entire Tutorial