Not sure what "like magic" means. But I'll offer suggestions that may get you closer to that goal.
- First, to make it a dotted line, first draw a short line, one that will be a single dash in your dashed-line. Turn its visibility off (I left it turned on in the screen shot below, so you could see it). I'll name this layer "Single Dash".
- Next, you'll draw your Bezier line as in my article.
- In the bezier line's Outline properties, change Brust Type to Image, and drag the Single Dash layer into the image source well. This will create your dashed line.
- To animate it, first with the playhead at the start of the timeline, keyframe Last Point Offset to 0. Move the playhead to the end of the timeilne, and keyframe that to 100%.
- To make it "travel" as I think you're trying to do, move the playhead to the start of the timeilne. Then drag the First Point Offest slider slowly to the right until 3 dashes (or how ever many you want) show. Keyframe the First Point Offest to that. Move the playhead to the end of the timeline, and adjust that parameter to taste, keyframe.
- Adding a Drop Shadow could help give it some depth.
- Making the Group a 3D Group, and adding a camera, moving the camera along, maybe some special lighting, could make the whole thing really cinematic.
You'll probably want to experiment with these settings, too. And don't forget you can put a Fade In/Out behavior if needed. Let me know if this helps, or if you have any further questions.