You push the ANY key which is located on the front of your computer (its sometimes hiddenly called the reset button ) 🙂 j/k
No PHP is just simply put a text file. Text that gets run by the PHP engine and outputs some data. Sounds to me like you dont have PHP installed on your system or that your httpd.conf file needs tweeking. (You do have a webserver running??). So to answer your questions:
1) Open PHP with any text view (Windows: Notepad, Linux/Unix Emacs or Vi)
2) Make sure that you have the following installed:
Web Server (ex apache)
PHP
PHP/Apache Mod
3)Setup your httpd.conf file to accept PHP as a mime/type
Check all this and it should run.