ZB-Pro Router issue in large network

Thank you very much. so do you have any code i can load on the arduinos board to text the communication? secondly, i think i just needed to set them on the same PAN ID? is there any other parameter i need to change? lastly, i mine suppose to use AT mode or API mode to be able to work on mesh network?
Thank you very much....really appreciate
I have been struggly with this for the past two months.