Hi. This lesson will introduce angular modules and how to get started using them. Angular modules help to organize and provide structure for your application. They group together the components, services, directives, and other source code needed to provide a specific feature or application function. It's important to note that despite the name, angular modules or NG modules, aren't the same as JavaScript modules. JavaScript modules and angular modules are separate structures, but of course can be used together. Every angular application has at least one module, which is the root module. This is the module that handles the whole of the angular application. Modules also assist with the compilation process and this is the first module that's loaded up by angular. This is a basic root module file. First, it needs to import NG module from the angular core library. NG module is a class decorator, which you can see here. This provides configuration data for the module, including any extra or external dependencies that need to be imported for use in the application or in this specific module. When working with angular, you import different modules as you need them. So if you wanted to use the different features angular provides for forms like validation or the NG model directive, you need to import the form module first into the file and then import it into the module. Importing modules from an external library works in a similar way. For example, if you wanted to use the front end component framework material, you would first install the material library and to do this, you would open a terminal window and run the commands ng add angular/material. And once that's installed, you can follow the same process of first importing the module into the file. And for this example, I'm gonna import the progress spinner component from material. And then add that to the imports array of the root module decorator. This progress spinner module contains a component that you can add to the templates. And now that we've imported the module, we can use it in the application. Deleting all of that starter code, I'm gonna add the spinner component. And make sure to save the files. Then run the command ng serve to build the application. And then opening the app up in a browser window, and you can see the progress spinner displaying here. So that's it for this lesson, introducing modules. And the next one you'll learn about the decorator and metadata more in depth.