The ST-12 will give you step-by-step instructions on how to do this job. There's no magic to the job. It's straightforward. It's not difficult, except for one thing. When was the last time this job was done? Mine wouldn't come out. Mine had been in there for many years, and without lubrication. I had to take the knuckles off, and bring them to a machine shop. Guy heated them, and pounded on them with a BFH tool.
The ST-12 shows a picture of a technician pounding them out from the bottom with a drift. They shouldn't need much, if any, pounding. When you go to put the new ones in, you'll find they fall out on their own through gravity. They can come out from the bottom or the top.
If you remove the knuckles, mark them. They can go on the wrong side. You'll only find this out after you've done the work to install them.