Basically, you must follow the instructions listed by ungn in the link. You don't have to separate the lower ball joint. Just disconnect from the frame. When you insert the new spring, and jack the lower arm into position with the floor jack, the problem is lining up the holes in the saddles with the holes in the A-arms, hence the "big screwdriver"/crowbar/prybar. It's much easier to do if you have a helper. Spring compressors are very dangerous.