Do you mean the encoder?
The first row (where I have the wires) are from the encoder on the motor. The other row is for connecting to the Arduino (eg. to an interrupt pin). I wasn't using that personally so you could omit them, ignore them, or tape them up somewhere.
I think the circuit just "ors" the two encoder outputs together so you can have a single interrupt pin (labelled INT on the board) which you connect to an interrupt (eg. D2/ D3) and then to see which way it is turning (if you care about that) connect ENC1 and ENC2 to some other pins.
I didn't care about the encoder as I was driving "visually", so I didn't need it to know exactly how much the wheels had turned.