A nice tune, tabbed upon request.
It could have been a wonderful calm song, but with all the choirs, strings, echoes and drum fills, I find it hopelessly overproduced.
Regular or low G (preferred)
Very slow, and accompanied in slow quarters, which you better keep in the background.
Quite straight forward, only the two main parts tabbed (not the ending)
Part [ B ]:
If you master the F-chord in the barre fingering (5553), use it here. It has the advantage that the melody notes nicely ring into each other
Same for the D-minor (barre second fret, 2453).