Watch the A Waltz For Leah online guitar lesson by Adrian Legg from Fingerstyle Revisionist: Adagio Songbook
Let's take "A Waltz for Leah" apart. It might look quite complicated, but really it's just a lot of little simple bits stuck together. There is an issue we need to talk about first however: The numbering in tablature. It's become a habit for some people to number tablature from the capo, making that "0". It doesn't work and it doesn't help you learn your fingerboard at all. This is also problematic for using a half capo, which has half the numbers from the nut and the others from the capo, which doesn't make much sense either. I recommend always numbering the frets from the nut no matter what the situation.
This piece is tuned in DADGAD, with a capo at the fifth fret. Let's go slowly through the first part of the piece.