intertion point can someone help me to continue to lisp code

I am stuck not understand how you must separate the first IPT, I read about car cdr cadr caddr I do not give out all the other point that should do

(defun c:cp1mm ()
;imput
(setvar "Cmdecho" 0)
(setq ipt (getpoint"\nSelect the bottom left point: "))
(setq lun (getreal "\nLength ofcabinet :"))
(setq adc (getreal "\nDepth of cabinet : "))
(setq hinal (getreal "\nHeight cabinet: "))
(setq nrc (getreal "\nNumber of cabinet: "))
(setq thc (getreal "\nThickness of cabinet: "))
 	(setq gpfl (getreal "\nThickness of PFL: "))
 	(progn
  (setq lun1 (- lun (* thc 2))))
 	(setq lun_pfl (- lun thc))
 	(setq lat_pfl (- hinal thc))
(command "_.box" "_non" ipt  "L" thc  hinal adc)
 		(command "_.box" "_non" ipt1  "L" lun1  thc adc)
 	(command "_.box" "_non" ipt2  "L" thc  hinal adc)
 	(command "_.box" "_non" ipt3  "L" lun1  thc adc)
 	  	(command "_.box" "_non" ipt4  "L" lun_pfl  lat_pfl gpfl)
(setvar "Cmdecho" 1)
(princ)
)

plase help me with my code

Maybe you can study the code behind this lisp program that will draw 2D cabinet elevations to gain some further insight.

http://cadtips.cadalyst.com/2d-operations/draw-cabinet-elevations

Thanks a lot but I'm looking for

very simple

(setq ipt (getpoint"\nSelect the bottom left point: "))
(setq x (car ipt))
(setq y (cadr ipt))
(setq z (caddr ipt))
;To put back together
(setq newpt (list x y z )) ; do not really need z 
;alternative
(setq x (nth 0 ipt))
(setq y (nth 1 ipt))
(setq z (nth 2 ipt))
; a box
(setq toprt (list (+ x lun) (+ y hinal)))