The compressor rod hooks onto the plates via 3 prongs at the top of the rod that fit into notches on the plates. You remove/insert the rod by lifting it up and twisting it so it passes through the holes in the plates. The LCAs on our cars all have a hole at the bottom which is aligned with the middle of the spring. This allows the MB spring compressor to enter/leave the center of spring when the spring is installed. The car was engineered to use a special tool for suspension work.
I bought this tool so if my car was too low for the winter here, I could change the springs back. I'll post a big picture thread of my car when I finish some other works in progress