Just purchased a K4 spectrum without sound.


I have not yet opened the tender but am going to add Tsunami DCC with sound to it.
The diagram seems to indicate a PC board inside the tender but some questions are not answered in the assembly instructions.

Toyed with doing it to my olde bowser loco but the backmann is a much finer locomotive.

Is the pc board designed to take a plug in DCC sound decoder?

What is the wiring from the engine to the connectors on same.

Can we presume the 2 pin are the lights and the 4 pin are the motor & wheel pickups?
If true what goes where?

Thanks

Allan