Just look at wp_nav_menu
arguments:
<?php
$defaults = array(
'theme_location' => '',
'menu' => '',
'container' => 'div',
'container_class' => '',
'container_id' => '',
'menu_class' => 'menu',
'menu_id' => '',
'echo' => true,
'fallback_cb' => 'wp_page_menu',
'before' => '',
'after' => '',
'link_before' => '',
'link_after' => '',
'items_wrap' => '<ul id="%1$s" class="%2$s">%3$s</ul>',
'depth' => 0,
'walker' => ''
);
wp_nav_menu( $defaults );
?>
You can use menu_id
argument to set its id
attribute and menu_class
to set its class attribute. You can set containers id/class attributes as well.