Ok, let me show you an example.
parts of human2_idle.gani
PHP Code:
SPRITE 100 HEAD 0 0 30 30 head up
SPRITE 150 ATTR1 0 0 40 40 hairs up
SPRITE 170 ATTR13 0 0 40 40 mask up
ATTACHSPRITE 100 170 -4 -8
ATTACHSPRITE 100 150 -4 -8
Sprite #100 is the head, right? The two ATTACHSPRITE will attach sprite #170 and #150 to the head image, with an offset of -4x and -8y.
Makes any sense now?