How to hide a forum completely?

I try to set up a forum for parents of disabled persons. It is supposed to be a closed group where the forum messages are visible only to invited members who must know the correct url in order to enter the forum by password. Only when inside they are allowed to see the messages. 
The forum name or content should not be found by search engines.
I can not find a setting for this in the admin panels. 

As a sideline I also need to make it impossible to send messages found at in the forum by e-mail to outside parties or to any social network.

I am grateful for guidance or to be informed if this is not possible.

Hello,

Create a group first for the members then:
Did you try via the forum permissions?:
Admin Panel >> General >> Categories & Forums >> Permissions   
Make sure that the 'View forum' is only checked for that group
> Saved

Only forums visible to guests are to be facilitated by bots / search engines.

Thank you. It was not obvious to me being a newbe  

Glad I could help. :DFeel free to ask new questions.

Solved // Moved