If you're interested in turning your show into an Alexa Flash Briefing Skill, you'll first need to create an Amazon Developer Account, and you can follow this guide here.
How to get your Alexa Flash Briefing feed URL
Click on Distribution at the top of your show's dashboard.
Scroll down to Other Integrations and select Alexa Flash Briefing.
Copy the feed URL.
Note: Your Alexa Flash Briefing feed URL will look like your normal feed URL with a slight modification at the end