Well, I think that the beginners guide is slightly outdated as nowadays NetworkManager can handle wifi connections as well as wired ones.
Just run netconfig
as root, choose 'loopback', input your hostname and domain name, confirm and you're all set.
Then, if you don't see the NetworkManager widget, just run as regular user "nm-applet" and it will show.
BTW, this works under Fluxbox as well, I'm using it right now