If after the initial setup you get no connection via wired or wireless through the router/firewall...or even before you get to that point you should determine if your ISP (assuming broadband) locks the MAC address to the original computer/device that it was setup for. If this is the case you'll need to tell your router/AP to do mac cloning and enter in the address of the original computer's network card.
Other than that and what was posted on the physical setup more details are needed as to what you are having a problem with.