How to add IPs to a CentOS Server?

I wanted to know how to add the Prefix, the usable range & the subnet mask. I'm a completely new to this field so I would need step-by-step instructions. Thanks in advance.

Regards,
Netizen

P.S. I've no control panel installed.

Assuming you want to do it permanently

Create a new file /etc/sysconfig/network-scripts/ifcfg-eth0:1

DEVICE=eth0:1
BOOTPROTO=static
IPADDR=192.168.0.2
NETMASK=255.255.255.0
ONBOOT=yes

Then issue ifup eth0:1

If you just want to add an IP temporarily (or without persistence between reboots).

ip addr add 192.168.0.2/24 dev eth0

The /24 represents the netmask 255.255.255.0 in CIDR notation

Google first before asking on SF, your question is exceptionally well covered on the internet.