I haven't done it on a celica yet, but all cars are about the same. That rubber thing should look like a hard piece of yellow plastic that slips onto the rod, you'll have to cut that in half I think. The instructions should tell you.
They talking about the center lock nut that goes on last to bolt everything down onto the shock. I think they want you to use brand new ones, cause if you ever buy shocks, they always come with new locknuts.