FREAK, think of the forums as if they were file cabinets, folders and papers. You can lock a cabinet, but you cannot lock a folder or a sheet/stack of papers
Picture your forum like a records office or a book store:CATEGORY
= SECTION. This is only shown if there are items below it. Basically, if you walk in to a book store and there is no "Science Fiction," They wont be saving a spot on their floor for that section. But if they keep the Science Fiction in the back, and locked away; only the people that know about it (or have access to it) will know it exists and can visit that location. Basically, those with access to the forums within the category, can see the category. Those people without access to any forums below this cat, will have the category section hidden out of their view.FORUM
= FILE CABINET, can be made private to only certain groups (people with keys). Everything within this forum can only be seen by people who have the correct access.TOPIC/THREAD
= FOLDER, if you can open the cabinet, you can read the topics/posts/replies/messages inside it. A topic is like a folder which stores all these individual bits of content. You cannot make these individual things private. Access to these is based on their FORUM container.POST/REPLY/MESSAGE
= PAPER, these things are stored inside each folder, and they all relate to the same thing as folder's label. You cannot make these individual things private. Access to these is based on their FORUM container.
Pardon my backward post. I meant to ask can you make the entire forum private in one step.
1) Control Panel > Forums/Forum Settings
2) Click on "Permissions" next to the forum you want to edit.
3) expand the "Can see this forum" section in the top-left
4) put a "0" next to each group that you want to hide that forum from. Use a "1" to display the forum to that group.
5) click the update button, and you're done.
do this for each forum.