How can I add a fixed vertical menu to my site? [closed]

I’m new to WordPress myself, but I think answering questions is a good way to learn. There may be a way to use hooks, but I couldn’t figure that out, so went ahead with directly editing header.php.

I tried the following:

From Appearance, Menus, I added a new menu and named it Vert_Menu_test

I chose to add the menu to the top left corner of my test site: In my header.php file, at the very beginning of the body, I added this code (based on this doc)

<?php
$defaults = array(
//'theme_location'  => '',
'menu'            => 'Vert_Menu_test',
'container'       => 'div',
//'container_class' => '',
'container_id'    => 'vert-menu-div',
//'menu_class'      => '',
//'menu_id'         => '',
'echo'            => true,
'fallback_cb'     => false,
//'before'          => '',
//'after'           => '',
//'link_before'     => '',
//'link_after'      => '',
'items_wrap'      => '<ul id="%1$s" class="%2$s">%3$s</ul>',
'depth'           => 0,
//'walker'          => ''
);
wp_nav_menu( $defaults );
?>

I gave the container div the id “vert-menu-div”. (See above.) So, in style.css, I added

#vert-menu-div {
    position:fixed;
    background-color:#eee;
}

This was enough to get the basics. A vertical menu fixed to the top-left corner. Good luck.