1Q7’s answered the question partially already, - most routers have a combined switch functionality, so once you plug it in with another Cat5 (ethernet) cable, it will assign it an internal IP address.
To get this IP address, look at the IP for your machine, it will be within that range, so if your machine is 192.168.0.5, the printer might be 192.168.0.6, I’ve added my own Samsung ML2525W printer this way without issue, using the same method 1Q7 suggested, although I entered the IP for the printer directly, instead of just pointing it to my router (because I knew the printers address from pinging it.)