Sitemap assistance

If you look at www.live8081.com you will see on the left there is a flyout menu of the left when you hover over home. I need to put more menus under there (home). How do I do that within the sitemap file... are do I have to create another sitemap file.

Below is my current sitemap file.

<?xml version="1.0" encoding="utf-8" ?>

<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >

<siteMapNode url="" title="Home" description="This will take you back to your home page...">

<siteMapNode url="" title="Account" description="Look at your account settings here..." />

<siteMapNode url="" title="Inbox" description="Check all your messages both mobile and email..." />

<siteMapNode url="" title="Friends" description="Check your friends and who made you a friend..." />

<siteMapNode url="" title="Help" description="Need some assistance" />

</siteMapNode>

</siteMap>