Although this is outside the scope of this tutorial, see also the DocumentRoot and ServerName directives in your web servers configuration file. (on Apache this is httpd.conf).
Use your browser to access the file with your web access URL, ending with the "/hello.php" file reference. When developing locally this url will be something like http://localhost/hello.php or http://127.0.0.1/hello.php but this depends on the web servers configuration. Although this is outside the scope of this tutorial, see also the DocumentRoot and ServerName directives in your web servers configuration file. (on Apache this is httpd.conf). If everything is setup correctly, this file will be parsed by PHP and the following output will make it to your browser: