and here is something else

cutting windows and mounting is not hard,but like everything else it takes practice to get a professional look. Try to find an art supply place where you can buy some cheap boards to practice on; htey don't have to be the correct size, 8x10 will do fine. they should cost about a dollar apiece . start with a small window and keep increasing the size working your way to the outter edge of the board, more practice that way.