This song in Dropped D tuning started out as classical guitar piece but eventually the instrumental inspired some words to appear. Here is a demo recording of the original classical guitar piece:
And here is the song the instrumental eventually turned into. This is just the guitar and vocal with no overdubbing:
This song is in Dropped D tuning and uses the following chords:
The D5 and other chords can be played as usual in standard tuning, except for the Bb/F which in standard tuning is probably best replaced with a standard Bb chord. The open circle in the G chord diagram indicates a fingering that is included when the chord is first played and then removed. The numbered circles in the A chord diagram represent a little turn around that is done at the end of a verse with finger 1 played and then removed and then finger 2 played and removed.
D5 is a power chord and can also be played in Dropped D with just the low three strings open which is the way I play it in the second last line of each verse. D5 is technically an interval rather than a chord, but neither D nor Dm seemed to work when I was moving from the instrumental to the song and figuring out what chords should be used.
Here are the lyrics and chords:
And here is the music including the guitar tablature for the verse instrumentals, the chords and the melody: