First, how do forms work? Actions can call a page in order to process a form. There are many web developement platforms. Now lets move onto how to use PHP in a form, cause that's all web design is... =o!
When you specify a page in the action it forewards via PHP, and lists the parameters in the URL. You can also have it list them in the header by using the post parameter for the method field. A simple PHP script could.... lets talk about PHP first! ... AND we are back, cause he's talking about the print statement for a while. You can get post variables by using the special function $_GET("name_of_variable"); which will return the information from the form with that variable name if you used the _ command, post uses $_POST. There are also other built in functions like this, they can be handy to use, which is why we have the second book to this class.
PHP is similar to JavaScript, but it was grown in a garage. Then over time it got popular and standardized. Weakly typed, blah. Variables are weakly typed, he goes on about this for a while. PHP has preference to ints, instead of strings like JavaScript, Hornick doesn't seem to like this language.
In order to get the server to run PHP, you need to create a PHP file. This causes the server to process the page assuming there is PHP in it, the PHP actually goes inside <?php ?> tags or script tags.