made a template out of card board, transfered it and cut it out of 4mm ply, bought a 8x4 sheet fibre board and cut same. stuck the two together with impact adhesive. cut and stuck 1/4 inch foam around window so when i glued the board on , as you pushed, it compressed the foam at high spots that way it stuck all over. bought a remnant from local car trimmers stuck it on using impact adhesive ( carpet fitters contact spray in a can, not ordinary spray glue this is not up to it and goes manky )then sprayed the back of the board and the foam and carefully put it in place.same for all the other bits.