how it works running in php?

The php need to have compilers to run and execute the web pages. The php will allow to have dedicated site that will download it for you.
Here's are the many compilers that use in php web developtment as there as follows :
http://php.net

http://apache.org

http://apachefriends.org

http://wampserver.com

All of this is better,  i am using xampp for my local host development because it seems OK and great compiling web applications.

How is it install? here's how:

1. Go to http://sourceforge.net/project/showfiles.php?group_id=61776 and click "XAMPP Windows". If necessary, click the "1.7" link to expand the appropriate version, and choose to download xampp-win32-1.7.0-installer.exe.
   The XAMPP Control Panel in Windows
   Go to http://sourceforge.net/project/showfiles.php?group_id=61776 and click "XAMPP Windows". If necessary, click the "1.7" link to expand the appropriate version, and choose to download xampp-win32-1.7.0-installer.exe
2. Run the installer. If you want, you can choose to install the Apache and MySQL servers as services, which will make them start automatically every time you start Windows. If you don't choose this option, you will need to use the XAMPP Control Panel application to start the servers individually each time you need them. This may be desirable if you don't intend to use your servers that often.
3. Upon completion of installation, the XAMPP Control Panel will open (if not, click Start » All Programs » Apache Friends » XAMPP » XAMPP Control Panel). This tool lets you start and stop the various servers installed as part of XAMPP.
4. Start Apache and MySQL by clicking on the "Start" buttons next to each item. If prompted by Windows Firewall, click the button labelled "Unblock".
5. Go to http://localhost/. If you are directed to a page with the XAMPP logo, your installation was successful. Congratulations!Its Done:

For wamp server user:

Installing

Double click on the downloaded file and just follow the instructions. Everything is automatic. The WampServer package is delivered whith the latest releases of Apache, MySQL and PHP.
Once WampServer is installed, you can add other releases by downloading them on this website. They will then appear in the WampServer menu and you will be able to switch releases with a simple click.
Each release of Apache, MySQL and PHP has its own settings and its own files (datas for MySQL).

Functionalities

WampServer's functionalities are very complete and easy to use so we won't explain here how to use them.With a left click on WampServer's icon, you will be able to:
- manage your Apache and MySQL services
- switch online/offline (give access to everyone or only localhost)
- install and switch Apache, MySQL and PHP releases
- manage your servers settings
- access your logs
- access your settings files
- create alias  With a right click :
- change WampServer's menu language
- access this page

How to start

When you install WampServer, a "www" directory is created (generally c:\wamp\www). Create a directory inside for your project and put your PHP files in it.
Click on the link "Localhost" in the WampServer menu or open your browser and open the http://localhost address.

Add Apache, MySQL and PHP releases

WampServer allows you to install almost all the existing releases of Apache, PHP and MySQL so you can reproduce exactly the settings of your production server.
To add a new release, donwload it here and install it.
Then click on the WampServer menu and activate the release that you want to use.

Wait until the WampServer icon become white again and start to work.
Were done: this is to begin your project works >)