This video provides a system for guitarists to memorize the notes on the fretboard. It breaks down the musical alphabet, explains octaves, sharps, and flats, and then demonstrates specific patterns and tricks for finding notes on the low E and A strings, and how to apply those patterns to other strings to locate any note on the guitar.
The video explains that the "two strings up and two frets over" pattern, which works for the low E and A strings, doesn't apply to the D and G strings because the interval between them is different. For the D and G strings (and subsequently the G and B strings), the octave shape shifts to "two strings up and three frets over." The high E string mirrors the low E string's notes, just two octaves higher.