You don't really need to do anything. It should just work if its plugged in. Its been a while, but I believe your router should have the ip address 192.168.1.1 if its working - plug in power, plug a computer into a port, go to that ip address and poke around. That said, the WRT54G is a
pretty old router, and you've gotten a later, slightly crippled model with less ram than the original, which is worth knowing. —
Journeyman Geek ♦ 1 min ago