Started shifting rough. Went to check transmission fluid, where is it? 97 cadi deville

On the drivers side under the hood beneath the rubber (big) hose going to the throttle body you will see a red cap turn it counter clock wise to remove, the transmission should be at operating temp. There is a dipstick on the bottom side of the cap. The marks are self explanatory. When putting the cap back on make sure you get it all the way on an tight. Note when you pull it out the first time wipe the dipstick off then put it back in and when you bring it back out that's when you get the reading, also when you are checking it the engine should be running, transmission in park with the park brake set.