Google Cloud Text-to-Speech

Hi,
I am looking to build a flow that will do 2 primary steps :

  • Convert a Text to voice (Text-to-Speech)
  • Cast this to a google home

I installed node-red-contrib-google-cloud and then I created my credentials (after built the project in my google and get the JSON file).

I have now built a Text to Speech node will all the set up ; language, gender, etc. etc.
It is where I am stuck now.

  • How can I define the text that I wanna transform?
  • After that, what I need to do with the output? I tried to send it to a File node to save it as a physical file.

Any help to give me a direction would be appreciated.
thanks