The Chromecast audio is a device that you cast music to. Have a look at the link below for more information about casting.
Just wanted to see if you still need help. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours if we won't hear back from you again.
Should that happen, feel free to create a new one if you have more questions or have other concerns in the future.
Thanks for the help, Cathal_S and Jeran.