Elseif Linux, Elseif *BSD, etc.
OP: You'll need more skillz than "hello world." 😉 Including:
Handling form data.
Storing data in files or a database.
Extracting data from said files/database.
Displaying output.
That last is pretty much HTML w/some variables, but the rest is, for lack of a better term, real programming. Rodney's given you some good pointers; my suggestion would be, start writing some stuff, and come on back to PHPBuilder when you have good questions; you'll usually get good help if you're civil and all that.
For your first script:
<?php
// a basic assignment statement
$text = "Hello, World!";
// print HW to the browser or command-line
echo $text;
// alternative syntax (currently commented out, won't run)
#print("$text");
?>
Good luck with PHP!