Brand new to React Native and Expo (lots of experience in React), simply following the docs here: https://reactnative.dev/docs/environment-setup?guide=quickstart and it states:

Now that you have successfully run the app, let’s modify it. Open
App.js in your text editor of choice and edit some lines. The
application should reload automatically once you save your changes.

But App.js simply is not present.

From there the confusion adds up as many components/plugins I am looking to use reference the App.js. I did find that in the package.json there is the line "main": "expo-router/entry", which I believe tells the app where to start, but it just seems like a lot of magic to me.

Should I not be using Expo? Is this a recent change? Thank you.