To insert it in a page, use the following code to load the necessary files:
<link rel="stylesheet" href="css/jqgrid.min.css">
<script src="https://code.jquery.com/jquery-1.12.4.min.js" type="text/javascript"></script>
<script src="js/jqgrids.min.js" type="text/javascript"></script>
<link rel="stylesheet" href="https://cdn.rawgit.com/pedrolaxe/Jqgrids/master/css/jqgrids.min.css">
<script src="https://code.jquery.com/jquery-1.12.4.min.js" type="text/javascript"></script>
<script src="https://cdn.rawgit.com/pedrolaxe/Jqgrids/master/js/jqgrids.min.js" type="text/javascript"></script>