It looks like you are using the Website Wizard. When you are editing your content areas, you will see two tabs at the top of the content editor window. One says Visual Editor and the other says Code Editor. When you are inserting HTML, CSS, or even Javascript, you need to switch to the Code Editor, find you place in the code, and insert it. Because of an oddity in the Website Wizards editors, do not insert you code at the very beginning. The Wizard will has a tendency to filter some stuff out.
When you switch back to the Visual Editor, you may not see anything. This is normal. Certain things will not operate while you are in the editor. You just need to save your work and then preview your pages. Once you have everything the way you want it, user the Wizards "publish" option.
Note that, not all code will work properly in the Website Wizard. Some of it has to be cleaned up a little to deal with the oddities of the Wizard's editors. If you have problems getting things to work, let us know.
