Unlike some years back when sites were almost exclusively static, the standard currently is to have a feature-rich, dynamic site. Not everybody can build this kind of web site completely from scratch though, hence the most convenient solution to have a dynamic website is to use a script application. Many website hosting companies offer script installers which you can use to add this sort of an app for each of your domain name or subdomains, so you'll not need to install anything manually. The main advantage of using an installer tool is that the scripts are ready to use in just a few minutes and the copy that will be installed is already with the settings required for it to run the way it should on the specific hosting web server, so you will not need to alter any script or account settings. This way you can quickly create one with just a few mouse clicks even though you may have never had a website before.