Question about Ethernet communication module

In Ethernet communication module manual, I am quite not sure about use of IP address and Protocol.
Chapter 6-5(attach file), talks about how to set IP address and Protocol.
but where is IP Address and IP Protocol come from???

thanks

Normally IP addresses are defined by you so that the devices are on the same sub-net which allows communication to take place. Do you have other devices that are already connected? What equipment is this for?

PLC is DL205, H2-ECOM100 for Ethernet communication.
Slave is Roborealm which is vision software.

I found IP address in Device 1 from my computer, but not found for Device 2 used as Modbus TCP.

Here is website from slave software. There are specific information but i don't still understand....
http://www.roborealm.com/help/Modbus_Slave.php