Follow each picture in order from start to end.
Read entire set before you start. This gives you a good idea of what to expect, without any surprises (oh, I dont have this tool, etc).
This DIY uses Mobil Delvac 1 full synthetic gear oil 75-W90, which I was able to reference to the replacement fluid Porsche recommends - Shell TF0951.
Replacement schedule is every 120,000 miles or 12 years. I would definitely not wait that long to do this. After 60,000 miles the fluid is not even translucent, has a very characteristic metallic smell to it. Similar numbers were stated for Cayenne turbo vehicles, and folks were all changing these fluids after 60k miles. I would do so here as well.
If you see anything that you know is not correct, please chime in so it can be corrected. Thanks and hope it helps.