How to connect itead arduino 3g gsm shield with arduino mega 256

Hello guys, nice to meet you, i'm new member in this forum. I want to ask a questions
I have itead arduino 3G gsm shield and arduino mega 2560. How to connect 3G shield with arduino mega 2560 in a physically?

Thank you

http://www.gsm-modem.de/M2M/m2m-componets/arduino-mega-gsm-gps/

Thank you