Hi @chrigel,

How can I give only certain members access?

I'm sorry, but this cannot be done. You can set forum accesses only for Usergruops, not the users separately.

 And registration / subscription should be confirmed by the administrator.

User registration is being processed through default WordPress registration system. Please search for Registration activation plugins, they should work for wpForo. These are two good examples:

1. https://wordpress.org/plugins/new-user-approve/
2. https://wordpress.org/plugins/wp-approve-user/