Ask HN: Creating funnels in Firebase Analytics

We're implementing Firebase Analytics and attempting to track user behavior using Firebase's Funnels feature. A basic funnel example would be something like: home_screen -> cart_screen -> checkout_screen

As of Firebase 3.8, screen_view is an auto-captured event. We have tagged screens with the Firebase screen name property, and confirmed that these are collected in debug mode. But when creating a new funnel on Firebase's web dashboard, I am only able to input screen_view into a funnel, not a specific screen (such as checkout_screen).

Does each screen need to be tagged with a unique event, or is there a way to add event properties into funnels? Appreciate your help!