registerRootComponent

I’m new to React Native. I renamed app.js to Gamescreen.js. I’m having Syntax Error with a Tic-Tac-Toe game I’m making.
My file structure is:
-components
Menuscreen.js
Square.js
TurnIndicator.js
-src
Gamescreen.js
I followed this stack: expo - How to define entry point for react native app - Stack Overflow
But I’m still having the error. I changed package.json Main to:
“main”: “TIC-TAC-TOE/src/Gamescreen.js”,

I also changed app.json entrypoint to:
“entryPoint”: “./src/Gamescreen.js”,

I added to the Gamescreen.js these lines:
import { registerRootComponent } from ‘expo’;
import { registerRootComponent } from ‘expo’; // import it explicitly
import { registerRootComponent } from ‘expo/build/launch/registerRootComponent’;

Expo.registerRootComponent(GameScreen);
export default GameScreen;

Please help