OpenCart: Add categories to main menu?

Question

I've just installed OpenCart for the first time, deleted all the dummy products and categories it comes with and added my own. However, now nothing appears in my menu - no product categories. I can't seem to fine where to add items to menus.

Can anyone point me in the right direction? Thanks

UPDATE:

THis is the php in my header tpl file:

?php if ($categories) { ?>
<div id="menu">
  <ul>
    <?php foreach ($categories as $category) { ?>
    <li><a href="<?php echo $category['href']; ?>"><?php echo $category['name']; ?></a>
      <?php if ($category['children']) { ?>
      <div>
        <?php for ($i = 0; $i < count($category['children']);) { ?>
        <ul>
          <?php $j = $i + ceil(count($category['children']) / $category['column']); ?>
          <?php for (; $i < $j; $i++) { ?>
          <?php if (isset($category['children'][$i])) { ?>
          <li><a href="<?php echo $category['children'][$i]['href']; ?>"><?php echo $category['children'][$i]['name']; ?></a></li>
          <?php } ?>
          <?php } ?>
        </ul>
        <?php } ?>
      </div>
      <?php } ?>
    </li>
    <?php } ?>
  </ul>
</div>

I have not acutally changed any of it from the original

Answer 1

Create a new parent category and sub categories in Catalog->Category->insert then add the new product Catalog->product->insert. Product should be appear in frond end. for more details see this video tutorials : http://www.opencart.com/index.php?route=documentation/screencast