add custom wordpress menu problem

Hi, Please “Help me build custom menu functions

<div class="nav">
			<ul>
								<li>
					<a href="#/forum"><span class="arrow">Forum</span></a>
					<div class="dropdown">
						<div class="columns">
							<ul>
															<li><a href="#/Thread-3">Thread 3</a></li>
															<li><a href="#/Thread-2">Thread 2</a></li>
														</ul>
							<div class="clear"></div>
						</div>
					</div>
				</li>
																				<li><a href="#/How-to"><span class="arrow">How to</span></a>
									<div class="dropdown">
						<div class="columns">
							<ul>
														<li><a href="#/Become-an-author">Become an author</a></li>
														<li><a href="#/Rates">Rates</a></li>
														<li><a href="#/Author-Tutorial">Author Tutorial</a></li>
														</ul>
							<div class="clear"></div>
						</div>
					</div>
								</li>
								<li><a href="#/Get-Started"><span>Get Started</span></a>
								</li>
								<li class="last"><a href="#/About-us"><span>About us</span></a>
								</li>
											</ul>
		</div>

Thanks