How to make a menu that is above the dialog stay below the dialog, in C

I want to place the create an application that has a menu, instead of above, below the dialog, because I want to create an application that (Just for me), ...

The code below is very simple, but it's really big:

Explorer.cpp:

#include <windows.h>
#include "resource.h"

LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    switch(Message) {
        case WM_COMMAND: {
            switch (LOWORD(wParam)) {
            }
            break;
        }
        case WM_DESTROY: {
            PostQuitMessage(0);
            break;
        }
        default:
            return DefWindowProc(hwnd, Message, wParam, lParam);
    }
    return 0;
}


int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
    WNDCLASSEX wc;
    HWND hwnd;
    MSG Msg;

    memset(&wc,0,sizeof(wc));
    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.lpfnWndProc   = WndProc; /* insert window procedure function here */
    wc.hInstance     = hInstance;
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wc.lpszClassName = "WindowClass";
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION); /* use "A" as icon name when you want to use the project icon */
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION); /* as above */

    if(!RegisterClassEx(&wc)) {
        MessageBox(NULL, "Window Registration Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
        return 0;
    }

    hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,"WindowClass","Caption",WS_VISIBLE|WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,640,480,NULL,NULL,hInstance,NULL);
    if(hwnd == NULL) {
        MessageBox(NULL, "Window Creation Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
        return 0;
    }
    
    // Load and attach the menu
    HMENU hMenu = LoadMenu(hInstance, MAKEINTRESOURCE(IDR_MAINMENU));
    SetMenu(hwnd, hMenu);
    
    while (GetMessage(&Msg, NULL, 0, 0) > 0) {
        TranslateMessage(&Msg);
        DispatchMessage(&Msg);
    }
    return Msg.wParam;
}

I tried using ChatGPT's help, but it didn't work

TDM-GCC 9.2.0 32-bit Release commands: -traditional-cpp -m32 -std=c++11 -mwindows