Hi,
In the first part of the code I register the menu… you can customize this with your own code to include multiple menus.
The enlightenment_before_header is just one place you can inject your own code… but the enlightenment template contains many of those places… so it basically depends where you would want the menu to show. Like I said, have a look at header.php to see which placeholders are there (or any other template file for that matter, footer.php if you would like to inject code in the lower part of the website).