Qusetion about wm8731

I use a MIC to give a signal into wm8731 throuth the "MICIN" pin,I want to set the sample rate at 8kHz and let the digital audio data output through the "ADCDAT" pin.While I want it output sound through "LHPOUT" pin and "RHPOUT" pin.

How should I configure the wm8731?

Which bit do I need to set?

Do I need to connect an external crystal?

English is not my first language,read the datasheet of wm8731 is difficult for me.Please help me,Thank You!