The CAGED Method for Guitar
The CAGED method is used to help learn where certain root notes and guitar chords repeat on the fretboard. CAGED stands for the names of the guitar chord forms used in the method (C - A - G - E - D).
The first step in learning the CAGED method is learning the open chord of the C major, A major, G major, E major, and D major guitar chords.
Starting with the C chord in the open position and using the other chord shapes (A - G - E - D), you can play more forms of the C chord up the neck of the guitar.
Using the CAGED Method
Starting with the A chord form in the open position, locate the other forms of the A chord up the guitar's neck by using the other chord forms: G-E-D-C (in the order of the spelling of CAGED with the chord forms). This works with each of the chord forms starting them in the open position.
The diagram below is of the A major arpeggio. Note how the CAGED method is moveable on the fretboard based on the root notes.
The diagram below is of the C major arpeggio. A major arpeggio uses the 1st, 3rd and 5th notes from its scale, C, E, G. This is a good example of using the CAGED method.