So far you have a site for Pandora (intpractise) which uses HTML, CSS and JavaScript to provide the front end of a reasonable site (or it could be if you hadn't been forced to use some awful styles). There is some PHP to add so you need to change the pages from .html to .php. Rename them now (or if Windows is hiding your file extensions you could open them in your editor and save as). You also need to change the links on all four pages so they point to the .php pages and not the old .html ones.