You unbolt the transmission pan and the fluid will pour out. Then you remove the filter that is above the pan that is held on with 2 bolts. You need to turn the engine over until the drain plug for the torque converter is at the bottom. Remove that drain plug to drain the transmission fluid from the torque converter. Reinstall the drain plug, reinstall a new filter, install a new pan gasket and bolt the pan back on. Refill the transmission with new fluid. Crank the car up and let it run for a few minutes and recheck the fluid level and top off if needed.
All that you seek (with helpful pictures too) is located here: http://taurusclub.com/forum/index.php?showtopic=57372
(Ford Taurus's do not have a torque converter drain plug and the filter is not held in place by 2 bolts)
(Ford Taurus's do not have a torque converter drain plug and the filter is not held in place by 2 bolts)