There are some good threads covering draining and replacing the transmission fluid. You will need to rotate the engine to line up the torque converter drain plug. Most people replace the transmission electrical connector when they replace the fluid. It is a $10 part and prone to leaking.
To fill the transmission, remove the cap on the filler neck (where the transmission dipstick would be if these things had dipsticks). Use a clean funnel to add fluid. The cap has a red locking pin which needs to be broken to remove the cap. I never replaced my pin, depending on the friction of the cap o-ring to keep it in place. I believe others do the same thing.
The picture below shows the transmission filler cap.