App.js

import React from 'react';
import 'react-native-gesture-handler';
import { NavigationContainer } from '@react-navigation/native';
import { createStackNavigator } from '@react-navigation/stack';
import Start from './components/Start';
import Chat from './components/Chat';

const Stack = createStackNavigator();

export default class App extends React.Component {
  render() {
    return (
      <>
        <NavigationContainer>
          <Stack.Navigator initialRouteName="Start">
            <Stack.Screen name="Start" component={Start} />
            <Stack.Screen name="Chat" component={Chat} />
          </Stack.Navigator>
        </NavigationContainer>
      </>
    );
  }
}