Look at the first 4 chords - this is an easy way to understand intervals better,and how chord names work.
In each case we are playing an A chord, but the top note of the chord is changing. Chord 1 is an A, with a high A note at the top of the chord - bring that note down a fret and you have a major 7th interval, so the chord is named A maj7. Down one more is A7 (or "A with a flat 7th") and down one again is A6 (or A with a sixth note added.) This approach works for all the other chords too. The scales are written in chord grids, then in Guitar tab and are the best choices for the key of A. On this chart you'll see some examples of 3-note chords - an easy and effective way of playing F sharp minor and Bm chords with using barre shapes. In the left hand column is a list of the chords in the key of A - also known as the harmonised scale of A. Songwriters will use this list, as options they know will work together in a song. Then we have 2 relevant scale patterns, A pentatonic is a simplified major scale,and the country scale is adding one more note - also good for Blues in this key. You could shift this pattern up 3 frets for a more blues sound.
