I was playing a bit on the Internet and decided to do an Internet search on window quilts. I thought maybe I might get some ideas for designs. (Planning ahead again.) I came across this site which has great information and a free down loadable instruction manual. If you want to get really fancy, and go to the expense of the hardware, you can get it all from the Warm Company. It's a batting company. Go to "products" on the bar along the top of the page then to "warm window". There you will find some good videos to watch about making and installing window quilts.
I won't be going to the expense of all the extra hardware but I did get some good ideas for my cheaper (frugal) version.