the easiest way of doing this is in my opinion is to play what you want through the sonos app, open the driver details (refresh the page if you haven't already), then copy string in the uri variable in the state variable section.
it should look something like this: x-rincon-mp3radio://http://ibizaglobalradio.streaming-pro.com:8024/
this can then be used with the playTrack command in the driver ui, or in any app that exposes playTrack from music players.
I imagine sonos's alexa enabled device has it's own way of working, I don't have one of them, but in any event that setup doesn't have anything to do with Hubitat's integration.
Thanks again! I am going to take all the tips and distill them into a post at some point ... one because as I get older I get more brain farts ... and so that others can pick up from my senior moments .... (Well ... not AARP Senior but ... yeah getting old sucks