Download the latest release on Github. And put the script at the bottom of your markup right after jQuery.

Download on Github

<script src="path/to/jquery.js"></script>
<script src="path/to/tocjs.js"></script>

Create an empty container to output the Table of Contents.

<nav class="toc"></nav>

Create a container that contains the target articles of the table of contents.

<div class="toc-src">
  <!--

  target article

  -->
</div><!--toc-src-->

Run the Plugin.

$('.toc-src').tocjs();