How do you add transmission fluid to a 1999 Cadillac STS?

To add Transmission Fluid to a 1999 Cadillac STS, first ensure the vehicle is on a level surface and the engine is running. Locate the transmission dipstick, which is typically found near the back of the engine. Remove the dipstick, wipe it clean, then reinsert it to check the fluid level. If it's low, use a funnel to add the appropriate type of transmission fluid through the dipstick tube until it reaches the correct level, then recheck the level after adding.