To install and run Angular 4 application, follow these steps:

Step 1: Install Node.js and npm

The first step is to install Node.js, the runtime environment for JavaScript that is required for Angular to work. Make sure you have Node.js installed on your computer, as it includes npm (package manager for Node). You can download Node.js from the official website, which offers versions for different operating systems. After installing Node.js, you need to verify that everything is installed correctly. To do this, just run a few simple commands in the terminal or command line to make sure that the Node.js and npm versions are displayed correctly.

Step 2: Install Angular CLI

Angular CLI (Command Line Interface) is a command line tool that helps you create, develop and test Angular applications. It makes it easy to create a project, add components, and launch applications. You can install Angular CLI through npm and after that you can use it to create a new Angular project.

Step 3: Create a new project

After installing Angular CLI, the next step is to create a new project. This is done using the Angular CLI command, which automatically creates the project structure and all the necessary files to get started. Creating a new project usually involves setting up basic components, routes, and other important elements.

Step 4: Launch the application

After creating a project, the next step is to start it. The Angular CLI provides a command to start the application on the local server so you can see how it will look in the browser. Once the server is started, your application will be available at the local address and you can interact with it and test the functionality.

Step 5: Development and Modification

Now that your app is up and running, you can start developing it, adding components, routes, styles, etc. Angular offers many tools for data manipulation, state management, and asynchronous content loading.

Once development is complete, the application can be built for a production version that is ready to be deployed on the server.

Thus, building and running an Angular 4 application is a fairly straightforward process that involves installing the necessary tools, creating a project using the Angular CLI, and running it to test the application.