Google said “content that makes sense for this live coverage carousel includes “live sports, elections, and breaking news” and “can include live blogs, full length articles, videos and more.”
You should use AMP HTML to take part in this. Here are the more detailed requirements:
Accelerated Mobile Pages (AMP) should be used while publishing content: Making use of AMP will allow your pages to be get loaded immediately to user’s devices.
Structured data markup should be used in AMP: It allows the preview for your live coverage article on the search page and also helps Google to understand the context around a piece of content.
Content should be pushed to Google with the use of Atom XML feed: You must use HTTP POST request in an Atom XML feed containing AMP page content immediately after it gets published on the web when you send content to Google.
This is a PILOT to select publishers and will allow Google to “surface content more quickly as compared to now”.