How to configure a LAN with 2 or more IP

I have to PCs in my office and I need to do the following:
The first PC has 2 LAN cards with UTP cables. One of them is connected to a local HUB and the other one to the second PC I have, which is an Internet server.
How to configure the IP addresses of the two LAN cards on my PC, and this which is a server, if the OS is FreeBSD ?