When you start the stunt course only the first track, Warehouse, is unlocked. To unlock the next tracks you need to complete the subsequent course.

To unlock all the bonus content like film stills, concept art, gallery, development, and movie credits complete the story mode.

When you first start, the only tracks unlocked are Hollywood 1 and L.A. 1. To unlock the other tracks you have to finish first in the tracks already unlocked.