According to other builder experience it is not easy to glue in the windows. The glue has quite a short working time and is not easy to handle. Based on an advice from a fellow RV builder in California who is a professional confectioner. I prepared a plastic bag to apply the glue.

There are no pictures on how I did it due to the before mentioned rather short working time of the glue.

I used some duct tape and foam to apply slight pressure to the window. I now hope that now crazing will appear.