I've never really studied the diagram and tried to figure out the internal schematic, but if you look at the diagrams for D and Y configs, you can see that in D, each input wire goes to an end of two coils. In Y, each input wire goes to one end of each coil, and the other end of the coils are connected. So, unsoldering/soldering the various bridges accomplishes this wiring.
Personally, it would have been easier if LMT simply brought the ends of each coil outside the motor and let the user figure out how to hook them up, like
this.