App.js

import React from 'react';
import {
  StyleSheet,
  Text,
  View,
  TouchableOpacity,
} from 'react-native';

import {createStackNavigator} from 'react-navigation';

class FristScreen extends React.Component{
  static navigationOptions = { header: null}
  render(){
    const {navigate} = this.props.navigation;
    return(
        <View>
		//when you press text you will navigate to second page...
        <Text onPress={() => navigate("Second")>First page...</Text>
        </View>
    );
  };
}//end


class SecondScreen extends React.Component{
  static navigationOptions = { header: null}
  render(){
    const {navigate} = this.props.navigation;
    return(
        <View>
		//when you press text you will return/navigate to first page...
        <Text onPress={() => navigate("Frist")}>Second page...</Text>
        </View>
    );
  };
}//end


const NavigationApp = createStackNavigator(
  {
    First: {screen: FirstScreen},
    Second: {screen: SecondScreen},
  }
);

export default class App extends React.Component {
  render() {
    return <NavigationApp/>;
  }
}