How do I add Coasting and Friction?

Please don't point me to the tutorial Smooth Camera Rotation! This truly does not explain how it works. Expect for attaching a preScripted js file. And Running it. I spent 2 day trying to figure out how they did the coasting. I've added the js file but I am unable to "Pan", cause the script centers the Annotation. So if someone can explain or create a script on the Pan Tool, and allow the annotation to coast with friction. That would be great!