Here are some links to articles and tutorials on how to get started in nodejs.
Express for nodejs tutorial
This is a great tutirial for getting started with nodejs. It shows how to create a package.json file and install using npm from there. This is important as a fast, reliable, and reproducable way to get the nodejs packages you need all in one place. The tutorial continues to show how to set up nodejs to listen on localhost port and also how to set up a basic router and directory / file structure.
Nodejs and PHP
Good article on using nodejs with PHP. I love php and it’s great they are compatible. That allows me to only apply nodejs for scripting some APIs (for example Bitcoin) and still use PHP as my main engine for serving dynamic website content.