Hi Jacob, Please make sure that the jQuery library is loaded before your jQuery codes or files.
Like this -
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
</head>
<body>
.....
.....
<script src="path/to/your_javascript_file"></script>
</body>
</html>
And slightly modify your file because jQuery is conflicting with WordPress and their are many solutions that you could use to avoid the jQuery conflicting.
One of many solution is to use like the below codes.
(function($){
$(document).ready(function(){
$('.__open').click(function(e) {
.....
.....
});
});
})(jQuery);
