Cast Kodi also analyzes the pages for videos, music or external platforms integrations. For example, if a page displays a YouTube video, this video will be sent to Kodi.
To cast videos / music, three items can be added on context menu of link / page / selection of videos or audio: Play now to Kodi, Play next to Kodi and Queue item to Kodi. A remote (accessible with toolbar button) is also present to cast current tab to Kodi and to: pause, go to next element, adjust the volume, …
To connect the extension to Kodi, you must Allow remote control from applications on other systems. This option is in Settings / Services / Control page in Kodi. You must also retrieve Kodi's IP address. This information is displayed in Settings / System information / Summary page. Then enter this IP address in Cast Kodi Options.