It’s pretty easy actually.
Just go to this directory:
Then you will see a file for eachnetwork port, for example my server is:
I already have the ifcfg-eth0 set up from the install but I want to use the second one for back ups so I just opened the file and added the IP to it. Then I made sure the rest of the setting smatched the first one other then the:
That line is specific to the network port.
So that is how you configure a eth0 or eth1 port.