How do you properly replace the rear windshield on a 92 Chrysler van? Got a good used one from a recycler?Thx?

There is still old urethane? on the replacement glass and the old urethane is still in the pinch weld on the van. Do I need to clean the old urethane off one or both? Any tricks for taking the wiper arm off?How do you properly replace the rear windshield on a 92 Chrysler van? Got a good used one from a recycler?Thx?
It would be best to get an experienced person to do it. Yes ALL the old urethane needs to be removed.