My apologies, I'd didn't notice this comment. Are you still looking for some demo code?

solved 

-The chips default buad rate is too fast and needs to be set to a lower rate by setting the Arduino to 115200, then setting the chip to a rate such as 19200, then setting the Arduino's boad rate to 19200. Use following code for the fix. 

GSM.begin(115200); // for GSM shield 

GSM.print("AT+IPR=19200\r"); //for SIM7600 

Serial.begin(19200); 

GSM.begin(19200);