You can't use 3 years old blog post exactly...codebase has changed so much since then...and the index page is now modular...so your specials thing needs to be a module.
Take the idea of that blog post, but not the code.
You need to make a module. A module consists of (usually) three files;
the module itself
the modules template file
the modules language file
So, take the new products module as a base...and by trial and error learn some code from it.
It's important that all shopowners know enough code to be dangerous...
/includes/modules/content/index/cm_i_new_products.php
/includes/modules/content/index/templates/new_products.php
/includes/languages/english/modules/content/index/cm_i_new_products.php
You need to copy each. Rename each. Open each, change each appropriately.
Save, upload, install. Forget.