Getting Set Up
To start off I'm going to give you a short introduction to Php, where its used and why I think its a good place to start for a beginner like you.
To start off you need to download one of the following depending on what operating system you have, WAMP for windows, MAMP for mac and LAMP for Linux. After that's downloaded follow the instructions on how to install it. I installed it here "C:\wamp", it makes it easy to access for what we need to do. Once you've installed it go to, My computer, C drive, and click on wamp, in there there'll be a folder called "www" where we'll be doing our programming. Create a new folder called "default wamp" in "www" and put the existing files in www into it. To access your server you'll need to type "localhost/" into the url bar. If you've skype or some sort of remote viewer or another server running you'll need to turn them off as they use the port required by *AMP.
Now you need to download and install Notepad++ from here for windows and Textmate for mac, from the macstore, the default Linux pad should be okay.
When thats done you'll be all set to start learning how to program!