One of the main things used when putting together the structure of your page are Divs, and they need to be positioned on the page. The four different types of positioning are: absolute, static, relative, and fixed.
Absolute is gets placed relative to the page unless there is another element on the page. You the use the top, bottom, left and right to position it where you would like. Static is the default for Dreamweaver, it will be positioned onto the page where is normally would be. Relative is positioning an element in relation to itself it moves top, bottom, left and right from where it was. And fixed is when you position something to stay on the screen even when the site is being scrolled up and down.