Welcome to... "Micro-Lesson 296"
The progression is performed using cross picking (applied with the flat-pick), to play through the; I - IV and V chords of the key, (G Major).
In measure one, we begin with an open position, "G Major chord," that is played from the 6th string's 3rd fret across to the 4th through 2nd strings. The bass-note shifts to the, "B" tone of the, "G" chord on the third beat. Here the upper chord tones are performed the same way as the first half of the measure.
In measure two, the IV-chord appears with an ascending picked concept, but it's arrival occurs as a, "suspended 2nd" style of chord. Into the second half of the measure, the "C" chord descends as a standard, "C Major."
In measure three, the tonic chord of "G," returns in the same fashion as we saw it used back in measure one. However, things change on the second half of this measure where we shift up the neck to a, "D," root. Here, the chord applied as a "Dadd4." This is a unique chord since it is both major, but yet also still applys the color of the added 4th extension.
In the final measure we return to the IV-chord and play through a guitar riff that uses the, "C Major," arpeggio as a way to transition up the neck into the 7th fret position. Here the, "Dsus4," appears as a way to produce tension and allow for the resolution of the progression by way of the V-chord (D Major).
Overall, the progression is not terribly difficult to play and allows for ample use /practice of several common open position chord types. Enjoy!
Micro Lesson 296: "G Major" Folk Chord Pattern