Hi, Amy. I'm afraid that you will not find much on window seats and what you might find will not be much help. Because of the many different bay windows, every window seat would have to be built to fit a particular location. What you basically want to do is to build a parallelogram shaped box to fit in the opening and then put drywall, solid wood or paneling on 2 sides of it. You would probably want to use 2x4's for framing the box and nail or screw it to the floor. Many people build the top with a hinged lid so that you can store things in the box. You might also want to get some foam rubber and fabric and make up a cushion.