Vocab: CSS stands for Cascading Style Sheets. There are two ways of using it, either in-page or calling a separate page with a line of code. The tutorials here will involve the latter. It's useful for chaning your layout or menu without having to recode all your pages. PHP Includes - Like a baby version of the PHP that involves databases, PHP Includes give you a way to design a website and keep elements (such as your header or menu) in a separate file, enabling you to change your whole site by changing that one file. Scripts - Scripts can mean a lot of different things (PHP scripts, JavaScript, etc.) but they generally all mean programming code you can put on your website to make things happen. For example, all the tutorials currently open in a popup window and I do this by using a JavaScript popup code.
BASIC CSS - The Basic CSS tutorial will cover how to set up a standard .css file so you can edit the style of your whole page by editing one single file.