from a command line type ipconfig/all
The gateway is the address that is assigned to the router (assuming you have it hooked up correctly)…
Unplug power on all units, then plug them all in.
Change the SSID to something besides the default.
Get into the router, and setup WPA encryption.
Get it to work, then I usually setup mac filtering.
From there you can turn off SSID display if you want.