Early A windshield replacement. How hard???

It has been a long time since I put a windshield in. I believe that you clean up well around the frame where the new one will go, put the gasket on the windshield and insert a string in the gasket which will allow you to pull the gasket in place. Sit the windshield in place with the string on the inside of the car. I had someone on the outside to apply some light pressure and I pulled the string working along slowly which brought the gasket in place.
I am sure you will get some better advise, but that is how we did it 25 years ago.