I once hosted a nice file for complete Natural Selection newbie mappers. It's an open-source sample map, which shows you the basics of how a ns classic map should look
Also I'm going to quote myself here from a while ago

I can't blame you for not searching, because the new search is wacky and the mapping faq is so out of date it probably has come around back to up to date

QUOTE(Kouji_San @ Nov 20 2006, 11:56 PM)

you're probably talking about ns_sample.map created by Chromeangel and hosted on nsworlds which is down, (http://nsworld.ns-central.co.uk/Main.php). A real shame it's down, it had a very nice colletion of maps.
However. I still have the file. I'll upload the *.map file on my isp host
ns_sample