The fingers of the gripping hand (for right-handers the left hand) are numbered consecutively. Thus the index finger = 1, middle finger = 2, ring finger = 3 and small finger = 4. These four fingers result in exactly 24 different possibilities for the sequence of the fingers.
In the notation the individual measures can be heard by clicking on the graphic, in the video the whole piece is played by guitar, viola and drums in Math Rock style.
The finger mathematics exercises are included in the Guitar Lovers Studies PDF or as play along track in the Jamtracks PDF which feature high graphic resolution for printing and integrated sound.