I dont know how the transformer is wound either. I know that putting the secondaries in parallel with double the current and that putting them in series will double the voltage. 2 voltages are specified so i know that each one is 12V but only 1 current value is specified. Im not sure if that is the current per secondary or the total current of both in parallel.

All transformers seem to be marked this way so i assume its a standard but i cant find any information on it