how do I get sub-forums to only show up when you click on the parent thread

like in cooling.. say I want a air cooled and a water cooled sections

but when I add them they always show up in the main forum page.
Also how would I go about adding separators to break up the main page into categories easier?

My test style I have created - it will not activate I have it set for user to select but in the user options it does not show up either.

...one more - my php files like the moderator.php - where do I find those? I am very new at this so thanks in advance for understanding.

frustrated!,
Joe

anyone?