how to connect 3 potentiometers, ADxl335,xbee,aurdino nano, dc motors

You would set the XBee that is connected to the Arduino in API mode. The ADX1335 Accelerometer connects to the ADC input of the XBee. (Make sure that the XBee you use can handle the 1.8 - 3.6V the ADX wants. Enable the ADC function on the XBee with the pins used.