Easy to set up CMS
I doubt that you find an even more easy to set up CMS than PowerCMS. All CMS that I know require a database (e.g. MySQL), need to parse PHP files (which is currently not the case on your server) and finally need some setup to connect to the database and inject the data into either a HTML page or a template.
You should definitely invest some time to understand how such a CMS works in general. Once you got that, you'll see, that it's quite simple to work with PowerCMS.
Regarding the PHP files on your server: you obviously run a Apache server, which is good. Usually these are set up in a way, that files with the extension .php are not delivered as such to the browser, but they are parsed through the PHP interpreter first and all PHP code within these files is executted and THEN delivered to the browser.
There are two ways to make this happen:
1. in a Apache config file, to which most hosting companys don't give you access
2. in a file called .htaccess which is a textfile, containing instructions for the Apache server
If in doubt, ask your hosting company to either set up the server (1.) or create the .htaccess for you (2.).
