This entry on the JourneyApps docs explains it well.
In short though, you need to add a basic webhook tag on the model in question in your data model, specifying only the
name attributes, like so.
<webhook type="ready" name="raw_webhook" />
Then you will need to complete the webhook config in the backend(s) for your application by marking the webhook as
enabled and by specifying the target
url. You do this from the
Manage webhooks interface of the backend, accessible from the context menu (elevated permissions may be required)