Here is the hook. You should press the second fret of the second string and the third fret with your index finger, press the second fret and the third fret with your middle finger, and then hook the sound.

Hold down the 2nd and 4th frets of the second beat with the index finger and the ring finger respectively, and then hook the empty string. Pay attention to this place that the hook action should not be too big, otherwise it will generate noise when touching other strings.

Practice hard, this piece is so beautiful.