I am having issues getting a demo for MySQL and PHP to work

I am receiving an error when following the instruction from https://www.phpzag.com/build-live-chat-system-with-ajax-php-mysql/ demo webpage. As instructed, I created SQL tables - chat_login_details and chat_users and MySQL is running when I try the demo. From the login.php page, I enter a user and password as shown on the page, and click the login button. The login.php page shows error - 'Error failed to connect to MySQL: Access denied for user 'root'@'localhost' (using password: NO)'.

Notes about setup: I have downloaded the zipped code into a folder - 'build-live-chat-system-with-ajax-php-mysql-demo' in the C:\inetpub\wwwroot folder (C:\inetpub\wwwroot\build-live-chat-system-with-ajax-php-mysql-demo). MySQL code is also running from this folder (C:\inetpub\wwwroot\mysql-8.0.23-winx64). I have IIS setup on Windows 10 machine.

I have googled the issue, but the solutions seem to involve updating the my.ini file that I do not have in the bin folder. I would like to get this application running as shown in the PHPZAG website. I am new to PHP/MySQL and I would like to understand where I am going wrong, how to fix and also instructions for getting this online.