Whenever I try to remove a windshield intact from a donor car, I work on the assumption that I can salvage the windshield or the rubber, but not both. Someone more skilled than I am can, no doubt, do better.
The first step is to inspect the windshield on the donor car well. Wash it well, and then sit inside the donor car and look at an external light source through the windshield from various angles. Even if the windshield lack major rock chip damage, it might still be in poor condition due to many minor problems that cumulatively make for a big problem. If you decide to proceed:
Close the hood and lift the wipers.
Using a flat-bladed screwdriver, take about twice as much time as you think is reasonable, and gently pry loose the amazingly fragile chrome-plated L-shaped trim pieces at the lower corners.
Use the same time management principle, remove the long chrome strip at the lower end of the windshield rubber. It is very easy to damage this part in the process.
The remaining structural element involves a plastic strip that makes the top and sides of the windshield rubber more rigid. Pull that out gently, keeping in mind that it might well be brittle.
The remainder of the work involves using a sharp knife to cut away the portion of the windshield rubber that prevents the windshield from being removed towards the front of the car. Cutting rubber is fairly tricky, and it’s easy to make the knife slip and get cut.
Make sure you remove all of the rubber that keeps the window in. Missing even a tiny section will create uneven pressure that can cause the windshield to crack when you remove it.
Before you remove the windshield, plan and prepare where you’re going to put it down. For me, it seemed less tricky to put it down with the center of the windshield facing downwards.