Unlike some years ago when sites were almost exclusively static, the standard nowadays is to have a feature-rich, dynamic website. Not many people can build this type of web site from scratch though, hence the simplest solution to have a dynamic website is to use a script application. Lots of hosting providers offer script installers you can use to add such an application for each of your domain name or subdomains, so you will not have to add anything manually. The main advantage of using an installer tool is the fact that the scripts are available to use within a few minutes and the copy that'll be installed is already with the settings needed for it to run the way it should on the particular hosting web server, so you will not have to modify any script or account settings. This way you can easily create one with only a couple of mouse clicks even though you may have never had a site before.