I believe what your looking for is how to configure the IP address on your network device.
Networking info is found in the file '/etc/network/interfaces' file. In order to add IP's you need to edit this file. For example, it probably looks like:
iface lo inet loopback
iface eth0 inet static
Generally, when you are adding additional IP addresses... you create them as "alias" devices to eth0 (unless you want to add them to a second interface card). Aliases are in the form of "eth0:0, eth0:1, etc". So, you will need to add something like the following for *each* additional IP address:
iface eth0:0 inet static
iface eth0:1 inet static
Then of course restart networking and verify...
Hope that helps.