DLMS Packet Format over Modbus

I want to get data from SCADA device using Modbus protocol. SCADA device is used in energy substation. Energy meter followers DLMS packet structure. I have knowledge on DLMS packet structure as well Modbus packet format. As Modbus packet structure needs registers of slave. But I don't have any idea how should I proceed for the next step. I want to know DLMS packet format over Modbus. So that I can move to firmware side easily.

Could you please help me to find out the solution?