widgetTreeDemo.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MaterialApp(
    title: 'Flutter app demo',
    home: Scaffold(
      appBar: AppBar(
        title: Text('Demo App'), //This text is displayed in the AppBar
      ), //AppBar
      body: Container(
        child: Column(
          //Column widget places its children vertically aligned with one another
          children: <Widget>[
            Row(
              //Row widget places its children horizontally aligned with one another
              children: <Widget>[
                Icon(
                  Icons.star,
                  size: 100,  //size property to set the size of the icon
                  color: Colors.yellow,  //color property to set the color of the icon
                ), //Icon
                Text(
                  'Hello',
                  style: TextStyle(fontSize: 100),  //TextStyle widget styles the Text widget
                ), //Text
              ],
            ),
            Row(
              children: <Widget>[
                //Try adding Widgets as you intend
              ],
            ), //Row
          ],
        ), //Column
      ), //Container
    ), //Scaffold
  )); //MaterialApp
}