(1) Positions refer to the left hand (on a right-handed guitarist). The left hand is the hand that fingers notes and chords on the fretboard.
(2) The following is from Wikipedia: In the left hand, each finger is responsible for exactly one fret. For each hand-position of four frets, the left hand is stationary while its fingers move… The ‘nth position’ means that the hand is positioned with the first finger [the Index] over the nth fret.
(3) Reminder: Conventional numbering for guitar strings is:
E = 1, B = 2, G =3, D = 4, A = 5, E = 6
(4) My homespun code for the places you put your fingertips to produce notes is SFN, “string-fret-note.” Example: ‘11F’ says, “Finger string 1 at fret 1 to produce an F.” Note: A “zero” fret means an open string — one not fretted.
(5) Here’s how the code would depict playing of a C scale in Position 1:
Notice the following:
a. String 6 (low E) is mute. (Its first C is on fret 8, which is beyond Position 1.)
b. Scale-note C launches on string 5 (the A string) at fret 3.
c. Notes D-E-F are all played on string 4 (the D string) first open, then at frets 2 and 3.
d. Notes G-A are played on string 3 (the G string) first open, then at fret 2.
e. Notes B-C (completing the octave) are played on string 2 (the B string) first open, then at fret 1.
(c) 2019 JMN.