Image rollovers

I'm a newbie, and trying to do a simple rollover image, with a link. The image is under some text, and when rolled over, swaps out to the specified image, and when clicked, goes to the link I provided.  I've copied and pasted the code from dreamweaver, with the associated javascript, and told sitefinity where the images were, but that didn't work.  How can I do a simple image rollover? 

Thanks!