Measure your bay window for bench seat. Measure height, length and depth. Take into account lid (seat) thickness. I used three-quarter inch oak plywood. Which gave me an overall height of 21 inches.
5.0 2x4 studs1.0 Level1.0 Tape measure1.0 Compound Miter saw1.0 Speed square 1.0lb Screws1.0 Stud finder1.0 Circular saw 2.0 Sand paper1.0 Finishing nailer1.0 Power drill1.0 Hardwood plywood1.0 Sandpaper1.0 Stain1.0 Air compressor1.0 Piano hinge bracket1.0 Brad nailer