There is a simple way of doing it.
See how should you install CSS3Menu on your page:
1. You should create your menu and publish it on a local drive in any test folder.
2. Open .html file from the saved folder in any text editor
(you'll find folder with images and .css file in this saved folder also).
3. Copy code for the HEAD section and paste it inside the HEAD/BODY section of you own webpage, for example:
<!-- Start css3menu.com HEAD section -->
<link rel="stylesheet" href="menu_files/style.css" type="text/css" />
<!-- End css3menu.com HEAD section -->
4. Copy code for the BODY section and paste it inside the Body section of you own web page in the place where you want to have a menu, for example:
<!-- Start css3menu.com BODY section -->
<ul id="css3menu" class="topmenu">
...
</ul>
<p style="display:none"><a href="http://css3menu.com/">Buttons Using CSS Css3Menu.com</a></p>
<!-- End css3menu.com BODY section -->
and paste it on your page in the correct place. You can do it in any text editor.
5. Now you have your page and folder with all images and style.css file.
6. You should upload them on your server.
That's all.
However, you can take a look at css3menu.com