Can someone help me to create submenu. My html code is :

Code:
<div class="nav-collapse collapse">
	     <ul id="nav-list" class="nav pull-right">
		<li><a href="#home">Home</a></li>
		<li><a href="#about">About</a></li>
		<li><a href="#updates">Updates</a></li>
		<li><a href="#screenshots">Screenshots</a></li>
		<li><a href="#howto">How to</a></li>
			<ul>
			<li><a href="#sub1">Sub Item 1.1</a></li>
			<li><a href="#sub2">Sub Item 1.2</a></li>
						</ul>
		<li><a href="#permissions">Permissions</a></li>
		<li><a href="#download">Download</a></li>
		<li><a href="#contact">Contact</a></li>
	  </ul>
			</div>
I have horizontal menu and want to have submenu.