We're trying to help you, but we can't help you if we don't understand what it is you are trying to accomplish.
So let me guess, again, what you're looking for, based on what you just posted.
Guess 1) Let's look at the main page of FlyerTalk Forums. You see "Miles & Points", then underneath that you see MilesBuzz!, Hotel Deals, Mileage Run Deals, and S.P.A.M. Are you wondering how to make it so that you ONLY see "Miles & Points", and don't see the four things underneath it? On the far right side of the dark blue "Miles & Points" box, there should be two little arrows pointing up, click that and you should only see the "Miles & Points" box, and not the other four things.
Guess 2) Are you trying to change the actual categories so that, for example, you can put what's under "Miles & Points" and move it to, say, "Travel & Dining"? If it's this you're looking for, you can't do it.
Guess 3) "The forums has topic categories then subforums in each of those categories, these categories can be hidden by pressing the down arrow (or exposing them, etc) I know I've seen somewhere to change this but now I can't seem to find it. " - Do you want to change a setting so that the little arrow is gone and every forum is visible automatically? I don't think there is a way to do that, but I'm not positive.
Guess 4) Are you looking to expand the "Airline Programs", "Global Airline Alliances", "Hotel Programs", or one of the other dark blue categories on the main page that doesn't have an arrow? For those categories, you have
to click on the category name, there is no way to expand them on the FT Forums homepage.
If it's not any of those guesses, I'm afraid you haven't given enough information for us to be able to help you. And if this is the case, I sincerely apologize, as I would love to help you, but I would kindly ask that you spell it out in as much detail as possible exactly what it is you want to do, or what you want things to look like, or etc. Help us help you, please.