To write .yml file to deploy .net application in Azure Virtual Machine

Hi Team, 

I am planning to write .yml file to deploy the web app in Azure virtual Machine with different environments(Like Dev, QA , UAT and Prod). Here I want to use variable group as well, I can update the web.config file base environment. 

Highly appreciate , if any one has knowledge , please share sample example , that will be great help to me.

Thanks

Jagannath