This is a way to play a transition from "Death Letter" to "Little Bird." I've heard lots of live versions where Jack joins these two, and he often leaves off the last verse of "Death Letter". I have, however, started this video at the last verse and then transitioned into the beginning of "Little Bird" so you can see one way to do it--experiment! This certainly isn't the only way, but because the "DL" secondary riff moves from the third fret to the second, I've found that it helps (as part of the "LB" riff moves from third to second). This is a pretty easy, pretty basic example, so play around and find something comfortable for you to work with. When I post covers of "DL" and "LB", I'll also post the explanations for those riffs if you can't see too well in the video. Cheers.