Then simply do the loading as that demo does it. When I exchange the magnet.obj with your supplied test obj file, I get the following indices:
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 3, 21, 4, 22, 23, 24, 9, 25, 10, 12, 26, 13, 15, 27, 16]