Follow a Guide

First open a new flash document and rename the layer to "guide".


On this layer create a line using the Pen Tool.


Then right click on this layer and click Guide.


You will now notice the icon by the layer name has now changed to a little hammer.


Now create a new layer and call it "object", on this layer we are going to put the object what will follow the guide.
Convert this object to a symbol, by highlighting it and pushing F8 or Modify > Convert to Symbol...
Then drag the symbol to the start of the guide. You will see the Registration of the symbol will change when on the line, and should snap onto the end.


Now on the timeline select another frame where you want the animation to finish and insert a new keyframe,
F6 or right click and Insert Keyframe. Now make this a tween, right click some where inbetween the keyframes and Create Motion Tween.


On the "guide" layer create a new keyframe below the "object" keyframe.
On the "object" layer move the symbol to the other end of the guide at the last keyframe.


Now drag the "object" layer under the "guide" layer so the "guide" layer icon turns to a black arrow.


The "guide" layer logo will now change to the completed guide icon.


Now test your movie and you should have something like this.