Let's try the example without the slides and tied notes just to get the banjo roll note groupings down. Try to remember that each group starts with the thumb. Each grouping also is just a group of two or three notes.
As you've also noticed by now, the fingerpicking pattern is the same for each chord. If you can get that down, the rest is simply memorizing a chord shape.
Last but not least, we'll introduce a three finger roll that uses four fingers. You'll find this to be a trademark of the Atkins style. With two kinds of rolls to play, the combinations you can devise over chords are limitless.