He was replacing the boots on his axle, which is why he disassembled it. If you're replacing the entire axle, as the vast majority of people do, then you stop after the third picture and pull the entire axle out of the car. I replaced the boots once, just because it was cheaper and I had a bunch of time, but it was not worth it, and I've never done it since. The control arm bolts to the subframe with just a single bolt. Follow the control arm to the subframe (the control arm is the aluminum arm with the ball joint in it), and you can see where it goes in. It takes an 18 or 19mm socket, if I remember right, and there's a hole in the subframe that you get to it through.
I'm not on Discord, so I'm not sure how that all works.
These cars have an odd front lower suspension setup. It's composed of two arms, a control arm and what Saab calls a stanchion arm. When someone refers to the control arm, it's this:
View attachment 278594
The vertical hole in the center with the huge bushing is what the stanchion arm bolts to. The horizontal hole on the end is where it connects to the subframe.
The stanchion arm is this thing:
View attachment 278595
It straddles the control arm, and then connects to the subframe behind the control arm. The metal sleeves shown in the picture go through the large round bushing and act as spacers.