The first thing we have to do is to pair the electrical socket or sockets to our Module. See the video below.The easiest way to do that is to make sure the power is disconnected from the Module. Then temporarily connect the 3.3V pin to pin D10 with a jumper wire. This is the Raspi Mode. Don't worry if you don't want to use Raspi Mode, you can dispense with it once pairing the sockets to the Module is complete.

Turn the power ON to the Module. Then press the pairing button on the socket of your choice. Usually this will result in a flashing light on the socket. You release the pairing button on the socket and then make pin D2 HIGH by connecting it temporarily to the 3.3V pin with a jumper wire. The socket will then turn ON.

If you wish to pair further sockets to pins D3 up to pin D9 then you can do so. Your Module is now paired with the socket or sockets. Turn the power off and disconnect the jumper wire from pin D10, unless you wish to remain in Raspi Mode. You can then choose whichever of the Modes you want by following the instructions in the Menu on the left (or below if you are viewing this on a phone).

If you wish to use the the Module in DTMF Mode then connect the jumper wire from the 3.3v pin to pin A1 i.e. your jumper wire should be connected to the 3.3v pin and the A1 pin.