For a little while the steps go like in the Marzocchi manual:
You unscrew the top, push the spring down and then you can completely unscrew the top and remove it. If you don't know what you're doing (like me!) and have the fork leg too far extended or if it's not in its vertical orientation, you'll spill oil all over the place at this step. Keep the fork leg compressed and keep it upright.
Then I get to this bolt on the bottom of the left fork leg. How do you get it off? This will ultimately be replaced by the new damping unit... but it's not clear how I can get it off. I keep on turning it CCW, and it rotates in place.
My impression is once this is off, the main fork leg and slider will separate.