Before going further to install NodeJS first we need to understand what is node JS and what is npm.

What is NodeJS?

NodeJS executes JavaScript code on a runtime so NodeJS is a Runtime environment to render data before delivering to a web browser.

What is NPM?

Npm stands for node package manager which is the engine or application for sharing JavaScript code.

Follow the following steps to install nodeJS and npm in Windows:

Step 1

Download Node.js Installer

Simple Wizard to install node.js simply next next and next ask you a some questions and then finish it 

Step 2

Verify Installation | Open Command Prompt and execute following command

node –v

It will return which version of node.js you had installed 

Check the version of node package manager npm 

npm –v