You don't need to put your IP address anywhere from what I can tell. The other users on the LAN should know your IP address (because you'll tell them what it is). Additionally, it's not necessary to register your server to the masterserver (as somebody already stated). Even if you do, it won't matter because if you haven't set up port forwarding nobody outside of your LAN will be able to connect anyway.
I just tried running ac_server.exe inside bin_win32 folder on the command line (I'm assuming you're using Windows, maybe wrongly), and it kind of works for me, except that it complains that it can't find the maps, but that is probably because I'm using the PortableApps.com version of AC (I usually just play, not setup servers). So I'm guessing if I corrected those path issues (by using the standard installed AC version instead), that I'd be all set.
Just try doing exactly what the page says that I linked to and see what errors you get back on the command line. I agree that the documentation could be a little more detailed but such is the nature of the open source community. I guess we should be thankful there is any at all. ;)
I just tried running ac_server.exe inside bin_win32 folder on the command line (I'm assuming you're using Windows, maybe wrongly), and it kind of works for me, except that it complains that it can't find the maps, but that is probably because I'm using the PortableApps.com version of AC (I usually just play, not setup servers). So I'm guessing if I corrected those path issues (by using the standard installed AC version instead), that I'd be all set.
Just try doing exactly what the page says that I linked to and see what errors you get back on the command line. I agree that the documentation could be a little more detailed but such is the nature of the open source community. I guess we should be thankful there is any at all. ;)