The pull-offs shown all drop to the third fret from the 6th or 5th fret.

Play this exercise from the third position, using your index finger at the third fret to 'anchor' your hand. Fret the 6th-fret notes with your pinky, and pull-off to the index finger on the third fret. Play the 5th-fret notes with your ring finger, again pulling-off to your index finger on the third fret.