this is the code
the red numbers correspond to the numbers to be excluded, separated by commas.
<?php wp_list_categories('sort_column=name&title_li=&depth=2&exclude=1, 7, 8, 9, 12, 13, 17, 18, 24, 26, 31, 32'); ?>
insert it in your header.php
scroll down until you find the subnav div
see below:
