In fact it’s pretty easy.
First of all you need to bend left and right sides of windscreen using same technique as described in our article about fuel tanks. But avoid to use too thin tools! There can be “fog” appears on the windscreen. Also I prefer to paint edges of windscreen. Finally you’ll have something like the part on the first picture:
Then bend windscreen with your fingers:
Don’t worry about “fog” – this is clear acetate plastic and there will be no fog till you bend it in about 90 degr.
And, finally, just push the windscreen from inside with your fingers:
Now you need to repair chipped paint, clear the windscreen and that’s all! Even no glue is needed.