It's hard without more clarity on what you mean by copying the data into the module. From the PLC or from external modbus devices and if you are using the module as slave or master. Project 101, like any other engineering problems, in other word.
Let's start from what you know. By now I assume you know what modbus device(s) you are going to talk to. Usually, you have no choice if these devices are slave or master and typically they would be slave devices. Give us a quick description or diagram of the communication scheme. You will also need basic working knowledge of modbus which you can learn readily on the internet.
With most Prosoft module, the module holds internal database made us integers. In Prosoft setup you then assign these integer to be modbus addresses and also PLC addresses. So for example, an internal module address of 100 can be assigned as modbus register 4000 and PLC address [300].
So Internal[100] = Modbus 4000 = PLC [300], so anything you MOVd or COPy into PLC[300] will become Modbus [4000] and vice versa.
The above works once you added the ladder logic as provided by Prosoft and also configured the Prosoft internal commands and setting with PCB (Prosoft Configuration Builder).
<note that I'm just giving an example of how database of a Prosoft module is handled and I haven't touched modbus in a while, actual address correspondence depend on your assignment>
When working with Prosoft it's best to keep a spreadsheet of how you set up the addresses and commands to keep everything straight. Prosoft also got great free phone support and they can walk through for you step by step if needed be.
