there are 2 lines at the auto cooler section on the radiator, where the lines come out of the transmistion over to the radiator, and back again.
simply drop one of those lines out, put one end into a bucket, and the other end (radiator end) stick some hose on the end. see which one is the return section and simply pump the oil out with the car running. and stop it once the oil stops comming out.
basicaly the auto will hold around 9 ltrs of oil, but if you do it that way it only drops about 4 ltrs of oil.
if you wanna do a full flush you do the same as above, but put one end into the clean oil, and the other end into one hell of a huge container. and run it till the oil comes out clean