Markup (html) contains elements, such as html, body, h1, h2, p, span, div and so forth. Hence a <div>-tag is part of an element; the other part being the </div>-tag.
The element structure of many web sites is basically (using HTML5 element names)
These elements can be positioned and styled using style rules (css). Depending on the style rules, the above structure can take on many different styles, without ever touching the markup.
Have a look here for a simple two-column layout using the same structure as above http://www.456bereastreet.com/lab/developing_with_web_standards/csslayout/2-col/
There are plenty of video tutorials, all you need to do is Google the subject. But none that I have come across that go at the same pace as the student.
This will probably help you more http://forums.adobe.com/thread/492638
I strongly recommend that you buy the following book`:
CSS: The Missing Manual
It is very well written and easy to follow. This will give you a good grounding on how to use and apply CSS.
In addition to this book it might ve be helpful to buy a book called 'The CSS Anthology' by Rachel Andrew. This contains all the code and explantion you need to create anything that looks like a table - such as a diary page etc.