title: npm install command - please explain
body: <p>I am starting to learn React Native and I am very new to npm package manager.  I read that npm can install packages localy or globaly but I am trying to understand what does that mean.
  I am reading this page <a href="https://docs.npmjs.com/getting-started/installing-npm-packages-locally" rel="nofollow noreferrer">https://docs.npmjs.com/getting-started/installing-npm-packages-locally</a>, can someone explain to me what does this mean please.</p>
  
  <blockquote>
    <p>If you want to depend on the package from your own module using something like Node.js' require, then you want to install locally, which is npm install's default behavior. On the other hand, if you want to use it as a command line tool, something like the grunt CLI, then you want to install it globally.</p>
  </blockquote>
  
  <p>Since I am very new to npm, React Native, Node (never used it), I am confused by the very first sentence in this quote.  What does it mean "my own module?</p>
  
  <p>If I want to use CRNA, I guess, I would have to install it globally?</p>
  
  <p>If I am to install a package, say CRNA locally or globally, where do I see it installed on my MacBook Pro?</p>