Watch the Kenny Smith/Ron Block Rhythm online guitar lesson by Stephen Mougin from Bluegrass Rhythm Evolution
For some slower tunes, both of these fantastic stylists will drop to a simple chord arpeggio, sometimes even including some non-chord tones to add color.
As you begin learning this style, don't worry so much about exactly which notes you're playing after the downbeat. As long as your left hand is in the correct chord shape, any string you hit will be a "correct" note. When you spend some quality time with it, you can dial in your specific note choice for each pattern or phrase.
(User listening tip: "When You Say Nothing At All" by Ron Block or "Lay This Broken Heart To Rest" Kenny Smith)