This will create a Total CMS menu of categories/tags/authors with a submenus of all posts in that are assigned to that category/tag/author

total-cms-category-post-submenu.php

<?php
$cmsid = "blog";
$attribute = "category"; // tag, category, author
$href = "/blog/?category="; // URL to blog list with category filter
//-----------------------------------------------
// Do not modify below this line
//-----------------------------------------------
if ($publish) {	
    $totalblog = new \TotalCMS\Component\Blog($cmsid);
    $attrs = $totalblog->list_attributes($attribute);
	
	foreach ($attrs as $attr) {
	    $perm = explode("=",$attr["params"])[1];
		$label = $attr["label"];
        echo "<li class='has-dropdown'><a href='$href$perm'>$label</a><ul class='dropdown'>";
        $posts = $totalblog->filter_posts([$attribute=>$perm]);
	usort($posts, function($a, $b){
	    return strcmp($a->title, $b->title);
	});
        foreach ($posts as $post) {
            echo "<li><a href='$totalblog->posturl$post->permalink'>$post->title</a></li>";
        }
        echo "</ul></li>";
	}
}
?>