To get started with SND's Messenger Experience, you'll first need to ensure your Facebook Page is registered within Facebook's News Page Index.
Any admin with access to a Page in Business Manager should see the “News Pages” option under the “Registrations” tab in Business Settings. This is where you can begin the process of registering your News Pages.
Once Pages are submitted, each Page and its associated website will be reviewed against the registration guidelines.
Facebook is also asking you to share optional information about your Page, like logos and editorial policies. They’re working closely with publishers and industry groups to find the best way to display this additional information. The goal is to allow your readers/viewers to have a better understanding of the news they see on Facebook. This information is optional, but if you want a chance to take part in Facebook’s early efforts around this initiative, you’ll want to give as much of that info as you can.
Once your page is added to the NPI, you'll be able to use the SND Messenger Experience!