Install Windshield on 69 Dart Sedan

All, I've read many opinions on how to install glass my eyes are bleeding and I'm really confused. I am out in the country so no chance of getting a glass shop here. I have done one in an A100 but it was 15 years ago. I used the rope with the gasket on the windshield. Can anyone here cut through the chase and really tell me their experiences for the best way. Also I dont remember any butyl on the windshield when it came out. Can it be applied later if there is a leak?
Thanks FABO