liomry:
So in order to stack this board I should solder on headers instead of directly to the board as shown and avoid reusing any pins that are used by the motor shield?
The instructions show male header pins. These are soldered to the bottom of the motor shield with the male pins pointing down. The male pins plug into the female headers on the Arduino.
If, instead, you get stacking headers (Shield stacking headers for Arduino (R3 Compatible) : ID 85 : Adafruit Industries, Unique & fun DIY electronics and kits) and solder them to the motor shield with the male pins sticking down you will still be able to plug the male pins into the Arduino and plug another shield into the female headers on the motor shield.
If the second shield conflicts with the first shield you will have to kludge some connections by cutting or bending pins and soldering wires.