The top picture the wires on the electrical cord are all separated, none are connected together. The heating element - R,S,T the wires go straight up just like the middle picture. The bottom picture the heating element wires U,V,W go straight down much like the top. You most likely won't have to fool around with changing the element wires.
For the most part remove the drain pan. Use a number 4 metric alan wrench and remove the 2 screws holding down the lid over the electrical box. You should now see the electrical switch. If you look at the diagram it shows that the switch should have one big jumper that crosses the electrical leads on the switch. To see what I mean look at the middle and the top diagram and you should see breaks in the white line. When you look at you switch and you see metal tabs jumping all the screw connectors then you are already setup for single phase.
If this is the case wire your plug red-black, orange-white, and green is ground.
