how create and modify code into Button and Edit

Take a look at this example. I'm not the author, but you can ask questions:
Code:
format PE GUI 4.0
entry start

include 'win32a.inc'

section '.data' data readable writeable

class     db 'FASMWIN32',0
title     db 'WINDOW',0
classb       db 'BUTTON',0
classe       db 'EDIT',0
classs db 'STATIC',0
textb1       db 'Copy',0
textb2 db 'Clear',0
textg db 'Frame',0
texts db 'Text',0
textc  db 'Clear all',0
errtxt    db 'Error',0
hwnd  dd ?
hwnde   dd ?                    ;Edit box 1
hwnds    dd ?                    ;Edit box 2 (read only)
hwndc        dd ?                    ;Checkbox
text       rb 100
form  db '>;CG5=> D09;>2: %d',0

wc  WNDCLASS 0,WindowProc,0,0,0,0,0,COLOR_BTNFACE+1,0,class
msg  MSG

section '.code' code readable executable

start:

 invoke  GetModuleHandle,0
   mov     [wc.hInstance],eax
  invoke  LoadIcon,0,IDI_APPLICATION
  mov     [wc.hIcon],eax
      invoke  LoadCursor,0,IDC_ARROW
      mov     [wc.hCursor],eax
    invoke  RegisterClass,wc
    cmp     eax,0
       je      error

   ;WS_EX_ACCEPTFILES @07@5H05B >:=C ?>;CG0BL D09;K Drag&Drop
  invoke CreateWindowEx,WS_EX_ACCEPTFILES,class,title,WS_VISIBLE+ WS_SYSMENU,128,128,256,192,0,0,[wc.hInstance],0
     cmp     eax,0
       je      error
       mov     [hwnd],eax
msg_loop:
 invoke  GetMessage,msg,0,0,0
        cmp     eax,0
       je      end_loop
    invoke  IsDialogMessage,[hwnd],msg      ; C6=> 4;O >1@01>B:8 A>>1I5=89 >:=C 480;>30
  cmp     eax,0                           ; A;8 C1@0BL, B> ?5@5E>4 <564C >:=0<8
  jne     msg_loop                        ; ?> TAB =5 1C45B >ACI5AB2;OBLAO
  invoke  TranslateMessage,msg
        invoke  DispatchMessage,msg
 jmp     msg_loop

error:
  invoke  MessageBox,0,errtxt,0,MB_ICONERROR+MB_OK

end_loop:
       invoke  ExitProcess,[msg.wParam]

proc WindowProc hwnd,wmsg,wparam,lparam
     push    ebx esi edi
 cmp     [wmsg],WM_CREATE
    je      .wmcreate
   cmp     [wmsg],WM_COMMAND
   je      .wmcommand
  cmp     [wmsg],WM_DESTROY
   je      .wmdestroy
  cmp     [wmsg],WM_DROPFILES     ;A;8 :B>-B> GB>-B> Drag&Drop=C;
  je      .drop
  .defwndproc:
 invoke  DefWindowProc,[hwnd],[wmsg],[wparam],[lparam]
       jmp     .finish
  .wmcreate:
 invoke  CreateWindowEx,0,classb,textg,WS_VISIBLE+ WS_CHILD+ BS_GROUPBOX,5,5,240,150,[hwnd],1000,[wc.hInstance],0
    invoke  CreateWindowEx,0,classb,textb1,WS_VISIBLE+WS_CHILD+ BS_PUSHBUTTON+WS_TABSTOP,20,100,100,40,[hwnd],1001,[wc.hInstance],0
     invoke  CreateWindowEx,0,classb,textb2,WS_VISIBLE+WS_CHILD+ BS_PUSHBUTTON+WS_TABSTOP,130,100,100,40,[hwnd],1002,[wc.hInstance],0
    invoke  CreateWindowEx,0,classe,texts,WS_VISIBLE+WS_CHILD+WS_BORDER+ WS_TABSTOP+ES_AUTOHSCROLL,10,25,230,20,[hwnd],1003,[wc.hInstance],0
    mov     [hwnde],eax
 invoke  CreateWindowEx,0,classe,0,WS_VISIBLE+WS_CHILD+WS_BORDER+WS_TABSTOP+ES_AUTOHSCROLL+ES_READONLY,10,50,230,20,[hwnd],1004,[wc.hInstance],0
     mov     [hwnds],eax
 invoke  CreateWindowEx,0,classb,textc,WS_VISIBLE+WS_CHILD+ BS_AUTOCHECKBOX+WS_TABSTOP,130,75,110,20,[hwnd],1005,[wc.hInstance],0
    mov     [hwndc],eax
 invoke  CreateWindowEx,0,classs,textg,WS_VISIBLE+ WS_CHILD,190,145,43,15,[hwnd],1006,[wc.hInstance],0
       invoke  SetFocus,[hwnde]
    jmp     .finish
  .wmcommand:
        cmp     [wparam],1001
       je      .but1
       cmp     [wparam],1002
       je      .but2
       jmp     .finish
    .but1:
   invoke  SendMessage,[hwnde],WM_GETTEXT,100,text
     invoke  SendMessage,[hwnds],WM_SETTEXT,0,text
       jmp     .finish
    .but2:
   invoke  SendMessage,[hwnds],WM_SETTEXT,0,0
  invoke  SendMessage,[hwndc],BM_GETCHECK,0,0
 cmp     eax,BST_CHECKED
     jne     .finish
     invoke  SendMessage,[hwnde],WM_SETTEXT,0,0
  invoke  SendMessage,[hwndc],BM_SETCHECK,BST_UNCHECKED,0
     jmp     .finish
  .drop:
     invoke  DragQueryFile,[wparam],-1,text,100      ; >;CG8< 2 EAX :>;-2> D09;>2 (?0@0<5B@ -1)
       invoke  wsprintf,text,form,eax                  ;0?8H5< 2 [text] AB@>:C form
   invoke  SendMessage,[hwnds],WM_SETTEXT,0,text
       invoke  DragQueryFile,[wparam],0,text,100       ; >;CG8< 2 text 8<O D09;0
          invoke  SendMessage,[hwnde],WM_SETTEXT,0,text
       jmp     .finish
  .wmdestroy:
        invoke  PostQuitMessage,0
   mov     eax,0
  .finish:
     pop     edi esi ebx
 ret
endp

section '.idata' import data readable writeable

library     kernel32,'KERNEL32.DLL',\
        user32,'USER32.DLL',\
    shell32,'SHELL32.DLL'

include  'api\kernel32.inc'
include        'api\user32.inc'
include 'api\shell32.inc'