Ads between categories

I currently am using the Template Conditions plugin for MyBB. I want to add some stuff between categories on the index.

Category 1
MY CONTENT
Category 2

What code would I have to use and what template do I need to add that to?

There are a few ways. The easiest would be

https://community.mybb.com/mods.php?action=view&pid=39

Hope this helps!