you say you got your network running.. in that case, each computer has a different ip address and they can communicate..
open the games on both pc's.. one of you needs to be the server. on the one that will be the server, go to the multiplayer section of the game and choose "start network game" or host game or whatever is similar. set the settings up and let it go.
then on the client, go to multiplayer and choose "find network game" or "find local game" etc. and it should broadcast the network looking for servers and find the server pc, then you can connect to it
otherwise you can try to connect directly, if the game lets you just put in an ip address of the server, then you can try to put the server pc's ip address there and connect