SRU/W Preference Schema?

[pedroparkero]

Good day! I would like to know what I can give as an input under the "preference schema" and "server information" form in the SRU/W server configuration. There is no example in the manual (because those fields are blank for the sole Library of Congress example). For instance, can NGL connect to a server with a password, and if so, where will I enter it? Is there a format? Can you give examples?
[I've searched "preference schema" and "sru/w server" in Google but sadly, the only relevant hit goes back to the manual I'm reading, so I need more information.]
Thank you very much for your valued help so far!