How to enable Node.js autocomplete for non-core npm libraries?

Hi,
Could I get instructions on how to let the editor autocomplete for the Node.js JavaScript file, and find the additonal modules in the require() statement?

I tried the following:

• Install  npm_modules directly in the project folder, using "npm install"
  
• With npm_modules directly in the project folder, add it as a Root in JavaScript/Libraries. IDEA calls it "head."
• Install npm_modules in the global location, using "npm install -g".
  

Thanks!
Miguel