If you want to test some web script you probably need a web server that can run PHP or other programing script. Its usually expensive to buy server if you in collage and want to test few of your assignment or project and its better to make own server on you local PC desktop or in laptop. If you setup alone all modules like Apache, PHP or MYSQL that could take lot time plus need other skills to setup and its better to just install whole package with WAMP in a single click.
WAMP is actually a package for windows that include Apache, MYSQL and a PHP module plus you could install other addons or module and it also come for Linux or MAC that you could find with LAMP or MAMP on Google. To install it you need few windows apps that you could see and download WAMP from here. After installation you will need to find a small quick lunch icon near time clock on taskbar, from it you can stop, start and restart services that are MYSQL and PHP plus you can open web directory. To open local server on browser you need to type localhost address on your browser from where you can use sqlbuddy or phpmyadmin for database setup.
I hope this small tutorial will help you and you should make sure other apps that use port 80 on your PC like skype or teamviewer should be turn off first to lunch local server. You can use alternative packages like zend, easyphp, denwer and etc if this WAMP package not work.