Beginner's Guide to Adobe Flash/Animation/Motion Tweens
Motion Tweening is an easy method of animating an Object on the Stage, using the Timeline. Motion Tweening can only be performed on a Graphic, a Button or a Movie Clip.
For example, place an Object on the stage. This, by default, will create a Keyframe in frame 1 of the Timelime. Right click on the Keyframe in the Timeline and select Copy KeyFrame from the menu. Now right click on a frame further along the timeline and select Paste Frames. You will see your Object appear in the same position on the Stage, and the frames between your two keyframes will have turned grey.
Making sure that your second Keyframe is selected (a red line should be over it in the Timeline - if not just click on it with the left hand mouse button), move your object to somewhere else on the Stage by clicking and dragging it.
You can now create your Motion Tween. Right-click the Timeline anywhere between your two Keyframes and select Create Motion Tween. The frames will turn purple and a thin back arrow will point from the first Keyframe to the second.
You can test your animation by pressing CTRL + Enter. You should see your object move smoothly from its first position to its final position.
Note that attempting to tween more than one object on the same layer doesn't often work very well. If you need to do this, it's probably best to put the objects on separate layers.