To plug in Xbox 360 via Ethernet to router:
1) Plug in cable to Xbox 360
2) Plug in cable to router.
3) There is no step 3.
To connect Xbox 360 via wireless LAN:
1) Buy Xbox 360 wireless adapter and attach it into the Xbox 360.
2) Turn on router's wireless settings.
3) Set Xbox 360's wireless settings via the Dashboard. You may want to use a USB keyboard to enter the WEP/WPA key, if it's a long one. Typing that in using the game controller is very tedious.
On the G5 side, all you need to do is install
Connect360, once it too is plugged into the router.