Newbie needs a little hand with setting up a private forum
 

I've fooled around with this for a while, but can't seem to get it right. Runing 3.8.1 I want to set up a forum that is can only be viewed and used by a group of about 5 to 10 members. I've set up the usergroup as a custom usergroup and added the title of the private forum, but it is still visible to both registered and unregistered users .

How exactly do I hide it from view from everyone except the small usergroup? I've gone to each user's registration page, the custom usergroup shows up unchecked then I check that group and save it, but is that the method to provide permission to the specific category?

I'm a little lost. . .