For both ears you can select what you hear from each input channel. The options are to hear the audio PreFader, PostFader, or not at all. Generally, you want everything set to Postfader.
Rec to SD1 or Rec to SD2
There are two SD cards in the left side of the recorder. The settings are determined based on your use of the audio and/or your desire to live mix or customize headphone output.
If you do not want to edit the audio afterwards or it is a single microphone recording:
If you plan on editing individual audio tracks afterwards: