sim900D GSM/GPRS module to arduino

hi,

im a newbie with arduino.. my project is all about sending a message using sim900D to a another receiver which is a normal phone. im using some kind of a sim900D GSM/GPRS module that already fits with arduino.. here's the specification of this module, gsm gprs shield.pdf - Google Drive.

im having these problems:

getting a stable network
sending a message to a receiver (regular cellphone)

.. pls help.. tnx!!