Rock in B minor (variant) — alternating bass fingerstyle
Same idea as the basic fingerstyle version on Bm, Em, A, D, 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
Em-Am-D-G, alternating-bass fingerstyle
Same finger playing, but the thumb alternates between two bass strings: a bass walk under the rock loop. The thumb has to run on its own before you add the fingers.
Chord progression — Bm
Bar 1
Bm
i
Bar 2
Em
iv
Bar 3
A
VII
Bar 4
D
III