Hello, thanks for your purchase.
This projects section in the Demo One Page works trough AJAX, this mean you need run your project within a local or online server like APACHE or NGINX to get it working. For a local server, probably the best and easy option is XAMPP:
https://www.apachefriends.org/download.html
We hope this helps!
Please try that and let us know if you need further assistance.
Kind Regards,
Rodrigo.
If you are satisfied with Porto HTML and our support, please leave your comment and rating on ThemeForest downloads page. That helps us a lot: https://themeforest.net/downloads