NestJS is a powerful and feature-rich framework for building web applications and APIs using TypeScript. It is built on top of the popular Express.js framework and is heavily influenced by Angular, making it a great choice for developers who are already familiar with Angular.

Before getting started with NestJS, it's important to have a basic understanding of TypeScript, Node.js, and Express.js. Once you have that, you can start building your first NestJS application.

• Installing NestJS: You can install NestJS by running the following command in your terminal:

npm install -g @nestjs/cli

• Creating a new project: Once you have the NestJS CLI installed, you can create a new project by running the following command:

nest new project-name

• Setting up the project structure: NestJS uses a modular structure, which makes it easy to organize and maintain your code. The main components of a NestJS project include controllers, services, and modules.

• Creating a controller: Controllers handle incoming requests and send responses. In NestJS, controllers are decorated with the @Controller() decorator. To create a controller, you can use the following command:
  

nest generate controller name-of-controller

• Creating a service: Services handle the business logic of your application. They are responsible for performing tasks such as data validation, database operations, and API calls. To create a service, you can use the following command:

nest generate service name-of-service

• Creating a module: Modules are used to group related controllers and services together. To create a module, you can use the following command:

nest generate module name-of-module

• Starting the server: Once you have set up your project structure, you can start the server by running the following command:

nest start

• Testing your application: NestJS provides a powerful testing framework that makes it easy to test your controllers, services, and other components. You can use the following command to run your tests:

nest test

In conclusion, NestJS is a powerful and feature-rich framework for building web applications and APIs using TypeScript. With its modular structure, it makes it easy to organize and maintain your code. And with its built-in support for testing, it makes it easy to ensure your code is working as expected.