starting from guitar scratch

All you need is 3 chords and the truth, according to legendary Nashville songwriter Harlan Howard anyway, which is almost the same as learning to play the guitar from scratch.  All you really need to be able to play 99.9999% of songs ever written are 5 major chords:  C, A, G, E and D and a couple of minor chords too: Em, Am and Dm.  A bit of rhythm doesnt go amiss either, so when you have your fingers on one of these chords (try a G), count to four and strum on every number…then add two strums a number, but slowly, as you don’t want to leave a gap when you change chord.  Try changing from the G to a C and then maybe a D, and this is really is all there is to it.