Joplat

I'm a complete beginner who's just started web designing. I am just getting to grips with Dreamweaver CS5. I have a client who's basically put me on a trial(!) This is probably not difficult. He's asked me to design a homepage for his shop - he has four images which resemble the four areas in his shop. He wants the user to be able to hover over each image individually and a drop down navigatin menu will appear on each image. The menu will include the various categories within that area. Once a category is clicked, the remaining categories will still be accesible via a navigation bar somewhere else on the page. How do I do this? Any help most appreciated.... Thanks Jodi