I can't tell if the problem is something like no extra ports or you expected the Chromecast to work without a video display. You may have to go get one of their audio only devices.
https://support.google.com/chromecast/answer/7022492?hl=en isn't clear enough. You need the TV to make it work.
https://store.google.com/product/chromecast_audio for example would be used when there is only audio.
am trying to connect my chromecast gen 2 to my surround sound as to not use up all the hdmi ports on my tv. My tv is an Insignia NS-55D440NA14 and my avr is an LG ts913es. Currently the chromecast is connected to an hdmi port on the tv and the avr has hdmi arc connected to the arc input on the tv. With this setup everything works correctly but I was hoping to plug the chromecast directly into the avr as there are additional inputs on it thus freeing up an hdmi input on my tv for another component. Any suggestions on how to make this work the way I want?

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