Several steps.

1. Quick start create project with create-react-native-app
2. Get debugger working with react-native-debugger
3. Set up Xcode and/or Android Studio environment and eject from Expo so publishing is possible

At this point you can develop with:

1. yarn start
2. in a new tab: react-native run-ios
3. debug with: "open rndebugger://set-debugger-loc?host=localhost&port=8081"

Then publish and profit 😀