With one license you can access the books from a server by moving the application database from your local machine to a folder on your server and then change the directory path in the NV2 workstation to that folder on your server.
If you are looking to go multi-user, you need to purchase two more licenses and register each machine. With three licenses you can have two users in multiple sets of books at the same time. Each machine counts as one license (server + 2 workstations).
The server machine should be a fast machine if it will be offering databases and handling requests from other programs that require random disk access (like NV2). See the NewViews 2.08 Manual > The Server for more information.