How do I use "One-to-one chats initiated by moderators"?

Hi!
1. How do I use "One-to-one chats initiated by moderators" with the chat plugin? I found out that you can only do one-to-one chats when users are in the chatroom and you click on a name in the userlist to start a private chat. But how does this work as a moderator?

2. Is it also possible for a moderator to see the user list in the chatroom, but not the users or contributors? If yes, what do I need to do to make this happen?