Basic question on adding a module to a project Follow

Just starting with WebStorm & node.js, so please forgive my ignorance...

I've got a "HelloWorld" program up and running in the debugger (Windows).

Now I want to add a third-party node module (call it "freddy"), I can download the source from github, and I can then put it into my project under ./node_modules directory.

However, when I run, it can't be found

module.js:340
    throw err;
          ^
Error: Cannot find module 'freddy'

to environment variables.

But that didn't seem to help.

I'm sure it's something really obvious...