One of the first things you should do in this case is check to see if your Ethernet adapter is supported by the Linux Kernel.
The following link will tell you just that.
Anyways, this is the first step...try that and see what you come up with.
PS. You should really look around on www.tldp.org
and invest time in reading various HOWTO's listed there. Many people spent many many hours writing them, for you and all other linux users to use for free.