Before dealing with how the link is made between components and the DOM, let's introduce the concept of module and how it's used to bootstrap the application.

Under the src directory in the project root, locate and open the main.ts file:

This file is the starting point of our Angular application. It is responsible for instantiating the main module of the application and the root component in it. To do so, we import a platformBrowserDynamic method from the platform-browser-dynamic module, which is a part of Angular. This method returns an object to bootstrap the application. The bootstrapModule method of this object is responsible for kicking off Angular by rendering the root component of the component tree. It requires the main module to be passed as an argument, so we import our module class AppModule and pass it to bootstrap:

The following code is from the main.ts file:

import './polyfills.ts';
import { platformBrowserDynamic } from '@angular/platform-browser...