1. Append following to your header section (in between `<header>...</header>`).
   GB_ROOT_DIR is the URL where static files are located:

       <script type="text/javascript">
           var GB_ROOT_DIR = "http://mydomain.com/greybox/";
       </script>

GB_ROOT_DIR should be absolute.
2. Append also following scripts and one stylesheet:

       <script type="text/javascript" src="greybox/AJS.js"></script>
       <script type="text/javascript" src="greybox/AJS_fx.js"></script>
       <script type="text/javascript" src="greybox/gb_scripts.js"></script>
       <link href="greybox/gb_styles.css" rel="stylesheet" type="text/css" />

   AJS_fx.js is optional, it's used for effects. If you don't wish effects, then don't include AJS_fx.js in your header section.
3. That's it, you are now ready to use GreyBox!