How can I use Chat for Customer Support?

Hello,

I have several questions concerning Chat:

- I'd like to use the chat plugin to answer questions to individual customers, so I'd like to limit the mount of users who can enter the chat to 1 at a time. How to do? And how to make sure not to miss any incoming chat requests?
- How can I customize the wording, i.e. "click here to chat" and so on?
- How can I limit the bottom corner chat to individual pages where to display the chat option?

Thank you for your time!