Drop downs

I’m a beginner to intermediate WP programmer. I’m trying to figure out how to do a simple drop down menu with nav that uses pages. I did drop downs on this blog that uses categories for the nav with just this code (no plugin):

<ul id="nav_menu">
   <li><a href="<?php echo get_settings('home'); ?>">Home</a></li>
   <?php wp_list_pages('include=2&title_li=&depth=1');?>
   <?php wp_list_categories('include=472,471,470,469,468,467,466,465,464,463,462,333,310,300,299,293,292,291,290,289,288,287,286,285,284,283,282,280,279,278,277,276,275,274,273,272,271,270,269,254,248,249,180,279,251,252,253,266,267,268,167&title_li=&depth=2');?>
   <?php wp_list_pages('include=2308&title_li=&depth=1');?>
</ul>

I’m trying to do the same for this blog that uses mostly pages for the nav and thought it would be similar, however, can’t get it to work. Here’s what I tried testing one item – the second one down (#2 is parent):

<ul id="nav_menu">    

<?php wp_list_pages('include=3&title_li=&depth=1');?>
<?php wp_list_pages('include=2,896,898,903&title_li=&depth=2');?>
<?php wp_list_pages('include=23&title_li=&depth=1');?>
<?php wp_list_pages('include=25&title_li=&depth=1');?>
<?php wp_list_pages('include=27&title_li=&depth=1');?>
<?php wp_list_categories('include=3&title_li=&depth=2');?>
<?php wp_list_pages('include=407&title_li=&depth=1');?>
            </ul>

I set up the pages so that the main nav (ID2) is a parent page and the drop downs are children but still won’t work.

Thanks for your help!