After transmission is hot: You need to take the auto trans clutch cover/vent off (if it isn't missing) and rotate the donut-shaped thing (which in a modern car would be called a torque converter) until there is a plug at the bottom. Open the plug and drain the hot oil into an oil catch pan. Let that drip all over the place, remove the drain plug on the side of the sump. I think it's a 14mm or 17mm hex -- you may need to get a special wrench for this depending on clearance. Drain that into the oil catch pan. Then let it drip all over the place. Then take off the sump and any related tubes that are connected to the sump (2?). Let THEM drip all over the place. Wash out the sump. Take the filter off that is revealed when you remove the sump -- it has an orientation that is marked on the filter. (I am assuming a round filter but some cars have one that is not round). Put on new filter, new gasket, new copper washers if needed for any pipes you removed from the side of the sump, and put it back together. (don't forget to plug the donut back up). Then add the recommended amount of fluid and start the car, then shift it trough the gears without moving, check the fluid, etc etc etc, then go for a drive and check the fluid again. then clean up all the trans fluid that is on your garage floor and take all of the fluid in the oil catch pan to the local oil recycling place. It's ok to mix it with motor oil in the recycling. Have fun!