Like the sandcastle example bikeRide(https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/index.html?src=KML.html&label=DataSources)
The question is how to generate that kml file?
And what does those labels in bikeRide.kml means?
To make it move should I use <gx:Track> label to contain those coordinates, right?
Also in czml vehicle demo, how to generate the czml file to make it move?
What's the difference between those two ways?