Adding the CSS to your page
Now we need to get the CSS into your html document. As you might have read in the introduction there are 3 ways of doing this, external, internal and inline. Which one you chose will depend on what you are trying to do.
External
An external style sheet is what you should use when you want the style sheet applied to the whole site, or at least a group of files. We do this by adding this code between the <head> and </head> tags.
We are using the <link> tag which surprise surprise links to things. rel="stylesheet" says what you linking to, a stylesheet, type="text/css" says what type of style sheet, a CSS one. And finely href="http://www.example.com/style.css" says were the style sheet is, you will want to change this. You can add as many external style sheets as you want too.
Internal
If you only want to add the style sheet to one file, you use an internal style sheet. This is also added between the <head> </head> tags.
Notice I added the comment tags in, this prevents older browsers, of which there are very few around, from displaying the CSS. This is just a good practice, you don't have to do it. Though I strongly recommend you do.
Inline
The final way is to add it directly to the element. This follows a slightly different format. You don't add the selector or the {}. It looks like this
<a style="color:red;" href="index.html" >
Now you now how to use it, you might like to look at a CSS Reference like the my one CSS cheat sheets to see all the rules and properties you can use.