Creating motion along a guide layer

  1. Draw your object. Convert it to a symbol or group the parts together (Ctrl-g)
  2. Select your ending frame on the timeline and make a keyframe there (F6)
  3. Move the object to its ending position
  4. Go back to frame 1 on the timeline and set tween=motion in the properties
  5. Test (press ENTER)
  6. Create a motion guide layer (right-click on the layer and choose Add Motion Guide)
  7. Select the keyframe in frame 1 of the guide layer.
  8. Use the pencil tool to draw your path, (use black pencil), from the center of the beginning position of your object to the center of the ending position of your object (it’s easiest if you turn on onion skinning for all frames)
  9. The object must be centered on the beginning and ending points of the motion guide to work. If not, select the free transform tool and use the arrow keys on the keyboard to move the object so the center circle is exactly at the end of the line.
  10. Press ENTER to test

Here's a better example: