Yeesh - Comedians.
Anyway, I assume that you have a handle on how to configure arena settings once your running, and simply want the "quick and dirty" how to get it running on 2+ computers.
It's wicked simple. On the more powerful computer, select the 8 Player Option from the main screen, then Create Lan Host, and give it a name.
On the second through eighth computer, select 8 Player, select "Select Lan Game" and choose the name you assigned your host from the list.
Voila.
EDIT -> Note, you have to be inside the same firewall, or (presumably although I've never tried) both endpoints on the same VPN for it to work. If you're really asking "How do I use Lan play to demo AH and I'm in Seattle and he's in Saratoga Springs" then that's a whole different ball game....