Create A Forum - Support Forums

I am a bit stuck!
I have created my forum, and have created a group for which some of the members will be part of, a bit of an elite group, as I want to make some of the boards so only these chosen members can post in these boards. If possible, so others can reply, but not start a post.
Any helps much appreciated

Thanks for a quick reply.
 
When I click on boards, it lists my boards, and to the right gives me the options of permissions, move or modify.
I am assuming I click permissions....
It then gives me the list of groups, such as Moderator, Admin, and the groups I have created, which happen to be called Manager and Staff. I am on one of the boards permissions that I just want managers to be able to post, but allow anyone to read. So I click on the tick box for manager, and then scroll over the advanced options, and press the set permissions. It then seems to accept this but remain on the same page, but the managers box is unclicked.
I created a test profile, who is staff, but can still post on this board.
Am I doing something wrong here?