I am trying to create a php website on
Pages you define in WordPress's backend are pages mostly setup for your users to view / read. They, by default, have this URL structure of
http://localhost/?p=123 (though this can be changed, but that's a whole different lesson).
To include a script file, upload the file to your folder structure where you have your website then refer to it in your
include statement as follows:
EDIT: You may also want to have a look into WordPress Page Templates:
Pages are one of WordPress's built-in Post Types. You'll probably want most of your website Pages to look about the same. Sometimes, though, you may need a specific Page, or a group of Pages, to display or behave differently. This is easily accomplished with Page Templates.