title: How to install jQuery Validate plugin?
body: <p>I am a novice in jQuery plugin's usage.   Now I am faced with adding a new plugin to my project.</p>
  
  <p>It is the jQuery Validation plugin.</p>
  
  <p>I downloaded the archive from <a href="http://jqueryvalidation.org" rel="nofollow noreferrer">the official site</a>.</p>
  
  <p>Content of this archive looks like this:</p>
  
  <p><img src="https://i.stack.imgur.com/vZf22.jpg" alt="enter image description here"></p>
  
  <p>As I understand, there are a lot of redundant files which I shouldn't install in my project (<code>demo</code> for example).</p>
  
  <p>Can you briefly describe archive structure and which files I should use?</p>
  
  <p><strong>EDIT</strong>:</p>
  
  <p>lib content:
  <img src="https://i.stack.imgur.com/P6Wjq.jpg" alt="enter image description here"></p>