[ProFifaLeagues]

You can go to the admin control panel > forums & Moderators > create a new forum > make a category (for example called: Administration) and below it add 2 sub forums, ( for example: admins and one for staff ) so you can have private admin discussions and private staff (admins+mods) discussions.

Ok, once added you can go back and go to the forum permissions.

Go to the administration category and select 'deny all'
the page will reload and everything is marked as red, NOBODY can now see anything, not even the admins.

So the next step is to go to this category and select the admin usergroup and click edit, then at the top are two checkfields, one for default permissions and one for custom, it is on custom, now set it to default, and browse down. ANd submit the page. Upon return of the overview you will see that everything is still red, except the admin group. You can now go and do the same for the staff forum so that shows visible too.

Finally to make sure staff can't read the admin forum you can go to this sub forum and click on edit permissions for the staff usergroups and change it to custom permissions and set can view forum permission to no (or just all to no).

Now you have the following:

Administration (category) [admins+staff]
|- admins (forum) [admins]
`- staff (forum) [admins+staff]

And this means you got yourself a private forum.