You may open a Flash file by clicking File > Open. A dialog box will allow you to select a file. The following demo is saved as GettingStarted/demos/FirstAnimation.fla.
This demo has a simple animation in it so that we may examine a somewhat complicated timeline. You will find that some of the layers have sections in blue. These are animations called "Tweens" which will be covered in a later lesson.
Keyframes are represented by either hollow or solid circles. The solid circle means that frame has visible content. The hollow circle indicates a blank keyframe.
The red playhead shows one moment in time. By dragging the playhead, you will see what the animation will look like when it plays. Press the Enter key (on a PC) or Return (on a Mac) to play the timeline in place. This is called scrubbing the timeline.