Ok if datasheet is missing thats a bumer and you have to tackle little by little. For testing, on the driver make sure you have a low current setting.
So far we identified there are 4 halves of coils, all independent from each other.
For a first step, lets identify which halves form which coil. And which halves are opposite to the other. Try pairs (halves) only, while ignoring the remaining 4 wires. For example using your labels, use A1-A2 and C1-C2 and simply not use any of the 4 others, leave them open. Try issue a move command. See what happens.
a) If motor seems to move at all, these halves belong to opposite coils.
b) If the motor does not move, then they belong to same coil.
If neither a nor b happens or is not very distinguishable between them, rotate the rotor by hand in other position and try again.
Again and same with B and D, etc. The point is to identify which halves form same coil. This way we can figure which belong together and which dont.
Last step is to check the halves coils direction. Lets say that from each coil, the top half has a direction whatever that is, and the bottom half could be reversed. If A12+B12 form a pair and still things dont seem to work, then reverse it to A12+B21. Same with the other coil. Beside the starting combo there will be other 3 possible combinations.
So far we identified there are 4 halves of coils, all independent from each other.
For a first step, lets identify which halves form which coil. And which halves are opposite to the other. Try pairs (halves) only, while ignoring the remaining 4 wires. For example using your labels, use A1-A2 and C1-C2 and simply not use any of the 4 others, leave them open. Try issue a move command. See what happens.
a) If motor seems to move at all, these halves belong to opposite coils.
b) If the motor does not move, then they belong to same coil.
If neither a nor b happens or is not very distinguishable between them, rotate the rotor by hand in other position and try again.
Again and same with B and D, etc. The point is to identify which halves form same coil. This way we can figure which belong together and which dont.
Last step is to check the halves coils direction. Lets say that from each coil, the top half has a direction whatever that is, and the bottom half could be reversed. If A12+B12 form a pair and still things dont seem to work, then reverse it to A12+B21. Same with the other coil. Beside the starting combo there will be other 3 possible combinations.