Dreamweaver. Can't change the colour of my links

I recently built a site using dreamweaver. I had the navigation bar words in a blackish gray colour to go with my design, but when I added the link to the words it turned blue and won't change back.

The wierdest part about it is that not all the words changed colour.

What do I do?

 

<a>'s or anchors are given a default color by the browser, and the code above is what you need to override the default styles.

 

where abouts in the code do I insert that?

and do I use the whole thing?

 

<link rel="stylesheet" type="text/css" media="screen" href="screen.css" />

Then create a new CSS file and put this inside