When I plug the above sample into an old version of the Craic app on my ancient iPad, I get two separate lines of music, with the words on a line below each, though not always spaced under the appropriate notes & with some peculiar long slur? marks going for multiple measures/ lines. Playback sounds both lines of music simultaneously. If you're only concerned about getting both to sound together, I give as example an arrangement I did of KINGSFOLD/Star of the County Down for me to play on concertina, when was trying to reconcile two versions with what I could manage to play that has both single and doubled notes:


X: 0
T: I Heard the Voice of Jesus Say
C:tune:  Kingsfold
L: 1/4
Q:1/4=130
M: 4/4
%%MIDI program 1 0
K: G
 [G/]F/|"Em" [B,E] [B,E] [CE] [A,D]|"C"  [DG] [DG] "D" [DA]  [G/][A/] | "Em" [GB] [GB]"C" A/G/  E| "D"  [A,3D3]G/F/ |"Em" [B,E] E [CE] D| 
"G" [DG] [DG]"D" [DA] G/A/ |"Em" [GB] [EB]"C" A/G/ [CE] | "Em" [B,3E3] B/c/ | "G" [Gd] [GB] [G/B/][D/A/] [DG]|"D"  [EA] [DA]  [DB] G/A/ |"Em" [GB] B/A/ "C" G  [CE]| 
"D" [A,3D3] G/F/ | "Em" [B,E] [B,E] E/D/ E/F/ | "G" [DG] G"D" [FA] G/A/ |"Em" [GB] [EB] "C" A/G/  [CE] |"Em"([B,3-E3-]  [B,E])|]
W:Lyrics were included in my version, next line a space between verses
W:
W:Next verse line
W:
W: arranged by Joanne Laessig

Ive just learned the basics of ABC in the last 6 months since I got the app, and found that if I looked through the music I'd downloaded as ABC, I could find examples of what I wanted to do, and started building up a cheat sheet of bits I needed after analyzing what had been done. Best of luck to you!

Joanne in Cleveland