* Open a new flash file (Ctrl+N).
New Document window will appear
Select General panel and choose Type: Flash Document . Press OK.
* If your timeline window is not open, press (Ctrl+Alt+T).
* Now you can see a single Layer called "Layer1" in your timeline Window.

* Select the first frame. Now go to your working area and draw any object. To start off with, may be you can draw a circle.This is going to be your initial object.
In the above demonstration, my initial object is a short line.
* Select frame 20 and press F6 to insert a new keyframe.
* Still keeping playhead on frame 20, delete the object present in your working area. Now draw a different object, may be a square.
In the above demonstration, I have drawn a long line.
* Select any frame between, 2 to 19 and select Shape from the tween pop-up menu in the Property inspector. Now your Layer will look something like the one shown below.

* Now press (Ctrl+Enter) to view your motion tween.

In the above tutorial, you learnt how to create a simple shape tween. Believe me, using this logic you can create n number of beautiful things. Here is a simple example just to trigger your creativity.

* If you have already finished motion tween, to see the combined effect of motion and shape tween