"...which way do you extract the large trailing arm bushes?"

With the tool properly installed—the only way it'll fit—the bushing is extracted toward the center of the car (away from the wheel).

"What does the special tool look like?"

The "tool" is a kit having about 6-8 items, including mandrels, sleeves, spacers, a BMF fine-thread center bolt, and so on. It's configured one way to extract the old bushing, and another way to install the new.