To update objects and relationships, there is no need to learn any additional code. You simply access the interfaces and properties, setting values as needed. An example of querying for a ProcessInstrument and updating the operating temperature is as follows:
' Begin transaction
Dim lcolTransaction As New ObjectDictionary(Me.SPFSession)
' Find an instrument
Dim lobjInstr As IObject = Me.SPFSession.GetObjectByName("CV-101", "IProcessInstrument")
' Change the operating temperature
With lobjInstr.Interfaces("IInstrument").Properties("Instrument_OperatingTemperature")
.Value = "150"
.UoM = "C"
End With
' Add this instrument to the transaction
lcolTransaction.Add(lobjInstr)
' Commit transaction
lcolTransaction.Commit()