We look at what I like to call 'Singer-songwriter 6ths' which can also be seen as the 6ths intervals on parallel strings.
This technique is used in many genres, from Jazz, Fingerstyle playing or Country guitar and in Pop and Rock styles.
Key ideas explored:
Implied chords, in the key of A, using the 6ths
How this translates on different strings pairs
How this relates to the major scale
6ths in A - D and B strings

6ths in A - G and E strings

All the chords in A major, played with 6ths
If you feel lost following the diagrams, try to also listen to how the implied chords sound to help navigate across all the chords.
What you might find is the 'major scale sound' of 'do, re, mi, fa, sol, la, ti (or si), do', which really is a fundamental part of western music and something we often experience quite early in life and then internalise as a complete sound. Call upon that knowledge to help your ear follow these chords and your hands will, eventually, follow as the shapes become more familiar.