https://willowtreeapps.com/ideas/how-to-use-flutter-to-build-an-app-with-bottom-navigation Note : this article is written from the above reference links. Step 1. Define our entry point Let’s start by opening the main.dart file the under lib directory. Next, delete all the code inside that file because we are going to write our app from scratch.Start by importing material.dart import ‘package:flutter/material. dart’;