Apple has not yet updated specific support documents for AirPort Utility 6.1. The Help files built into AirPort Utility 6.1 do offer a basic selection of "how to's" for most configuration questions.
Your best bet may be to continue to use AirPort Utility 5.6 and its associated support documents for the time being. Other than seeing a nice looking interface, there is no reason to use the downgrade to AirPort Utility 6.1 unless you really need to do so.