SoMachine Basic Modbus Read_Var help

Hi guys, I have an M221 and trying to read process data from a HACH controller via Modbus 485.

In the Read_Var function block I need to configure ObjType, FirstObj, Quantity and IndexData. Slave ID is 3 and I am using SL2.

So, say if I wanted to read to following registers,

Register #40001, Data Type Integer, Length 1, Description- Sensor Measure

Register #40005, Data Type Float, Length 2, Description - Sensor Temp

Register #40007, Data Type String, Length 6, Description - Sensor Name

what do I put into the Read_Var function ?

I am completely new to this and it's just not clear to me.

Thanks

John