You will struggle to make a modern bow without a professional woodworking shop and skills, as well as buying most of the parts. Instead search google for pictures of vintage bows before they had variable tension and lots of pieces. (The hair on a bow is horse hair.)The bridge is a little trickier because no two (handmade) bridges are the same and that changes how the instrument sounds. Do some research on the type of wood typically used and any basic guidelines for size and thickness, then take a shot at cutting/carving one. You could also have one laser cut.