There is an 11mm drain bolt. It’s small and the head of the bolt stands off from the bottom of the transmission about 1/8". The oil level plug is the same size and is located in the location shown in the diagram above. It’s on the driver’s side behind the wheel well. The fill cap is black and has no writing on it. It looks like small engine gas cap located between the battery and the engine, recessed pretty deep. You will need a long funnel with a 6" length of 1/2" ID vinyl tubing attached to it in order to get the new fluid in the transmission. Measure what you drain out and put the same amount back in (it’s about 5.25 US quarts). Run it through all the gears and drain and fill it again, and again if you want. When you are satisfied with the condition of what you drain out, torque the bolt to 106 in-lbs, run it through the gears and put it back in park and let it run until the transmission temp on the dash read 185 degrees (the temp needs to be between 185 and 203 degrees F). Leave the engine running in park, crawl under the vehicle and pull the level check plug (it helps to loosen it ahead of time). Let fluid stream out until it trickles, then replace the plug. If no fluid comes out, add about 1/4 quart and pull the level check plug again. If the temp gets above 203 degrees, you will need to turn off the engine and let it cool.
The thing about old age is you can’t remember if all these responses have been read before or not. Doesn’t matter. You don’t have to read it if you don’t want to. I used to do my own transmission fluid changes and it was always a mess. I think it cost $120 at the trans shop the last time they did the Pontiac. I just sat and read the paper. At the Acura dealer, it was under $200 for the trans, transfer case, and rear differential and I hardly had time to finish breakfast before it was done. Yeah, as an amateur, I’ve just decided to let the pros do it instead of me-every 30,000 miles. I write it down so I don’t forget.