The "How to Create a Simple Counter App using React Native" article might be slightly out of date. I kept encountering this message when trying to npx expo start I ran this command and re-ran npx expo start and everything started working.
I had no issues running the w command, but had issues with ios and android. I manage to setup my Android Emulator referencing the Expo documentation below.
Follow each step of the article before trying to run an Android emulation in Expo.
How to Create A Simple Counter App using React Native ?
Learn how to set up the Android Emulator to test your app on a virtual Android device.