I'm creating the game of chess in scheme, but do not know how to save and load game state is a part I have this code

(define-struct ficha(color se-movio? tipo-ficha ))
;;tablero lista de listas de  fichas
(define-struct estado (tablero turno fichaSel))


(define bpawn (bitmap "b-peon.png"))
(define brook (bitmap "b-torre.png"))
(define bcaballo (bitmap "b-caballo.png"))
(define bbish (bitmap "b-arfil.png"))
(define bquee (bitmap "b-reina.png"))
(define bking (bitmap "b-rey.png"))
(define wpawn (bitmap "w-peon.png"))
(define wrook (bitmap "w-torre.png"))
(define wcaballo (bitmap "w-caballo.png"))
(define wbish (bitmap "w-arfil.png"))
(define wquee (bitmap "w-reina.png"))
(define wking (bitmap "w-rey.png"))
(define board (bitmap "board.jpg"))

This is the board that is a list of lists

(define tableroini (list (list torreb caballob arfilb reinab reyb arfilb caballob torreb)
                       (list peonb peonb peonb peonb peonb peonb peonb peonb)
                       (list empty empty empty empty empty empty empty empty)
                       (list empty empty empty empty empty empty empty empty)
                       (list empty empty empty empty empty empty empty empty)
                       (list empty empty empty empty empty empty empty empty)
                       (list peonw  peonw  peonw  peonw  peonw  peonw  peonw  peonw)
                       (list torrew caballow arfilw reinaw reyw arfilw caballow torrew)))

I did this to save the state of the game:

(define (Guardar-en-archivo archivo)
(write-file (string-append Subcarpeta archivo ".txt")
               "game state"  ))         

But not as you insert the game state on "game state" for me to save the game

How I can do this ?