Tutorial "Visualizing Time Dynamic Data with Cesium Stories" not working


In the tutorial Visualizing Time Dynamic Data with Cesium Stories you show how you upload a zip, containing a CZML and 3D models. When I download that zip and straight away try to upload it into my assets and also select “KML, CZML, or GeoJSON (host without tiling)”, I always get the message “.kml, .kmz, .czml, and .geojson files must be uploaded individually.”.

The tutorial is pretty easy to follow, so I don’t know what I am doing wrong here.

Best regards!