CHMOD - newbie

Hello. I am trying to use CHMOD to disable directory browsing by public users. I want users to be able to access .htm files, but not to see the list of files a folder. (The folder contains a URL-driven game, so it's an easy cheat to just type ?.htm and find all the files listed.)

My issue is that I don't seem to be able to find references to the code or parameters needed to CHMOD this set of permissions. I ran across some sample code on another web site (CHMOD o-r directoryname/) that was offered as a way to do just what I wanted, but when I attempted to use it, it did not work. I seem to need some numerical codes. I don't know what 777 or 404 or any of those numbers mean. I don't find them referenced in the "Edit Custom Commands" section of SmartFTP, as the CHMOD tutorial suggested.

Can someone point me to a reference list of CHMOD codes, so that I can figure out which numerical parameters I need to set? Barring that, can some helpful soul suggest the correct code in a reply?

Thanks so much!

Edited: Never mind. Issue resolved.