First of all you need to create an 'override' folder and files, so leave the folder /classic/ or /template_default/ untouch. The basic of work is better from /template_default/ not from /classic/
Step 1:
Create a brand new folder example -> /mytemplate/
so there will be new folder at /includes/templates/mytemplate/
Step 2:
Create its subfolders such as -> mytemplate/common/
mytemplate/css/ and mytemplate/images/
these subfolders are the clone of the original subfolders from /template_default/
Step 3:
copy all the files that you want to change from /template_default/, in this case tpl_header.php from /template_default/common/tpl_header.php to /mytemplate/common/tpl_header.php
Those step above are basic step in creating override folder & files, it applies to every files that you want to CHANGE, just grab the copy from /template_default/ and paste it in /mytemplate/, and start work on that copied files. No need to copy file that you dont want to change.
By this method you leave the original files untouch and ZenCart will detect any override files and process it instead.
Now you can work on the files you just copied, inthis case -> tpl_header.php from the brand new folder /mytemplate/common/
If you copy correctly from /template_default/ you will see tpl_header.php line 44 will start like below, I copy the entire Header Navigation Div box and insert the 'specials' link that we want to put there.
<!--bof-navigation display-->
<div id="navMainWrapper">
<div id="navMain">
<ul class="back">
<li><a href="<?php echo zen_href_link('specials')?>">Specials</a></li>
<li><?php echo '<a href="' . HTTP_SERVER . DIR_WS_CATALOG . '">'; ?><?php echo HEADER_TITLE_CATALOG; ?></a></li>
<?php if ($_SESSION['customer_id']) { ?>
<li><a href="<?php echo zen_href_link(FILENAME_LOGOFF, '', 'SSL'); ?>"><?php echo HEADER_TITLE_LOGOFF; ?></a></li>
<li><a href="<?php echo zen_href_link(FILENAME_ACCOUNT, '', 'SSL'); ?>"><?php echo HEADER_TITLE_MY_ACCOUNT; ?></a></li>
<?php
} else {
if (STORE_STATUS == '0') {
?>
<li><a href="<?php echo zen_href_link(FILENAME_LOGIN, '', 'SSL'); ?>"><?php echo HEADER_TITLE_LOGIN; ?></a></li>
<?php } } ?>
<?php if ($_SESSION['cart']->count_contents() != 0) { ?>
<li><a href="<?php echo zen_href_link(FILENAME_SHOPPING_CART, '', 'NONSSL'); ?>"><?php echo HEADER_TITLE_CART_CONTENTS; ?></a></li>
<li><a href="<?php echo zen_href_link(FILENAME_CHECKOUT_SHIPPING, '', 'SSL'); ?>"><?php echo HEADER_TITLE_CHECKOUT; ?></a></li>
<?php }?>
</ul>
</div>
<div class="navMainSearch forward"><?php require(DIR_WS_MODULES . 'sideboxes/search_header.php'); ?></div>
<br class="clearBoth" />
</div>
If you see below the 'special' link that we just inserted, there is HEADER_TITLE_CATALOG which means 'Home'
So in your header will look something like this
Special Home Login
'specials' menas it will link to this page:
http://www.yourdomain.com/index.php?main_page=specials
If you want to change the link 'special' to another page/products, simply mouseover or go to any page and see the link that pointed there in your browser address,
example the privacy page:
http://www.yourdomain.com/index.php?main_page=privacy
so you can replace to ```php
<li><a href="<?php echo zen_href_link('privacy')?>">Privacy</a></li>
``` to make link to Privacy page for an example.
Hope this helps, please update your progress