The basic rule for websites is there is only ONE index.php per directory, and that controls what is displayed.
If you started with a hosting-company "website builder", then that index.php will 'own' the document root of your website .. you may have to remove that (remove the website builder and restore your site to just you having full control).
If you installed Wim's template in the pwsWD/ directory, then it should be available with no conflict by going to your.website.com/pwsWD/ in a browser. If you want that in the home directory (as your.website.com), then you'll need to remove the website builder stuff first, then install pwsWD in the home directory.