Add an Embed App to the page you want the floater to appear on—your main page is always a good bet. Make sure the app is set NOT to display its title, then copy the following snippet and paste it in:
<!-- Go to www.addthis.com/dashboard to customize your tools --> <script type="text/javascript" src="//s7.addthis.com/js/300/addthis_widget.js#pubid=ra-5b3256a93b6ecfa3"></script>
