Steering Shaft Universal Joint replacement procedure instructions needed

We have had the above vehicle, a GL wagon, for over 15 years and it serves as our "spare". The vehicle is in amazing shape for its age, runs good, everything works and looks good. Recently we had the lower ball joints replaced and aligned by a local tire and alignment shop. Upon return, I noticed a little loose motion in the steering wheel that was not there before the work was done. Checked the inner and outer tie rod ends and found no loose motion. It turned out the loose motion is in the steering shaft universal joint. I think the shop damaged it by trying to move the steering while the steering wheel was locked. Of course, they denied it.

What I need from you is a detailed procedure for replacing the steering shaft universal joint (Dorman 425302). I have a Chilton repair manual, but it does not cover the joint replacement.

Thank you in advance for your reply and for all the times you have helped me the past.