Hi, Have a problem implementing arduino_serial_gps model on Arduino Nano

I was trying to read Signals using arduino_serial_gps model on Arduino Nano but i keep getting Error evaluating 'InitFcn' callback of Arduino Serial Receive block (mask) 'arduino_serial_gps/Serial_Receive'. How can i change the port number to one as suggested in the model or set another serial pin for receiving the data ? Because the error seems to come from the same port is assigned to USB port to simulate it in the external mode and The serial receive silmulink block only allow the port to be zero.