You don't need to add yourself to the wheel group: when creating a user with adduser, it asks for additional groups, push the up arrow and the defaults are sufficient (the "power" group is what is needed for shutdown/reboot operations).
The commands in the ArchWiki assume that you have a consolekit session available, as it is when you run X (the .xinitrc files take care of that).
If you want to use them in the console, just prefix them with a "ck-launch-session": for example, if you want to reboot
Code:
ck-launch-session dbus-send --system --print-reply --dest="org.freedesktop.ConsoleKit" /org/freedesktop/ConsoleKit/Manager org.freedesktop.ConsoleKit.Manager.Restart