Hi,
I'm sorry because as I needed a higher speed of communication I finally used a couple of bluetooth to do so.
Anyway, if you are using the first shield of this link:
http://www.robotshop.com/content/PDF/dfrobot-arduino-shields-manual.pdfyou will only need to connect the APC220 where it is indicated to. If not, you will need to connect only four pins, 5V, GND, Txd, Rxd, be careful of not connecting the last two on the wrong way...
Connecting those four pins should be enough to get some communication at 9600 bps...
good luck!