To make the illusion of compression when hitting the floor, right click on frame 10 once again and create another motion tween. Notice that an arrow between frame 1 & 10 (in the blue area) represents the 1st motion tween.
Now, click on "modify", "transform" and "scale"
This will allow you click on the center top square, and while still hold down you mouse button, push the ball/ distort the ball.
You will then want to click out side the ball to get rid of the scale command and click back on the ball and drag it back to the bottom of the page.
Now right click in frame 14, insert a "keyframe". Hit enter to see the ball fall and hit the floor.
Step 5 (the wrap up)
Now with these same skills to make the ball return to it's original location by working backwards through the above steps. Begin with a motion tween from frame 14 to make the ball round ( using the scale command once again) and another to bring the ball back up to the top of the page.