Pop in D — alternating bass fingerstyle
Same idea as the basic fingerstyle version on D, A, Bm, G, but with an alternating bass: the thumb switches between two different bass strings instead of staying on one, for a fuller accompaniment ("Travis picking" technique).
Tips
Isolate the thumb's alternation on its own first, without the other fingers, until it becomes automatic.
Understanding this type of exercise
E-A-B, alternating-bass fingerstyle
Same finger playing, but the thumb alternates between two bass strings: a steady bass walk under the cadence. The thumb has to run on its own before you add the fingers.
Chord progression — D
Bar 1
D
Bar 2
A
Bar 3
Bm
Bar 4
G