Unlike some years ago when sites were almost exclusively static, the standard today is to have a feature-rich, dynamic web site. Not everybody can create this kind of web site from scratch though, hence the most convenient solution to have a dynamic website is to use a script app. Lots of website hosting companies offer script installers which you can use to add such an app for each of your domain name or subdomains, so you will not have to add anything manually. The key advantage of using an installer tool is that the scripts are ready to use in a few minutes and the copy that will be installed is already with the settings necessary for it to run correctly on the specific hosting server, so you will not need to modify any script or account settings. That way you can easily create one with simply a couple of mouse clicks even if you have never had a site before.