Помогите написать дочернее окно

#include <windows.h> 
 
#define    ID_Create_BD                             1
#define    ID_Save_BD                               2
#define    ID_Exit                                  3
 
LRESULT CALLBACK WndProc(HWND Otdel_kadro, UINT Message, WPARAM wParam, LPARAM lParam);
 
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int nShowCmd)
{
 
    WNDCLASSEX Class_registration = { 0 };
    Class_registration.cbSize = sizeof(WNDCLASSEX);
    Class_registration.style = CS_HREDRAW | CS_VREDRAW;
    Class_registration.lpfnWndProc = WndProc;
    Class_registration.cbClsExtra = 0;
    Class_registration.cbWndExtra = 0;
    Class_registration.hInstance = hInst;
    Class_registration.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    Class_registration.lpszClassName = L"[lexpenz.com] Win32.";
    if (!RegisterClassEx(&Class_registration))
        return 1;
    HWND Otdel_kadro = CreateWindow(L"[lexpenz.com] Win32.", L"Otdel kadro Win32.", WS_OVERLAPPEDWINDOW, 500, 300, 500, 700, NULL, NULL, hInst, NULL);
    if (!Otdel_kadro)
        return 2;
    ShowWindow(Otdel_kadro, nShowCmd);
    UpdateWindow(Otdel_kadro);
    MSG msg = { 0 };
    while (GetMessage(&msg, 0, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
    }
 
LRESULT CALLBACK WndProc(HWND Otdel_kadro, UINT Message, WPARAM wParam, LPARAM lParam)
{
    switch (Message)
    {
    case WM_CREATE:
 
        //Создание одельные вкладки
        HWND Create_BD, Save_BD, Exit;
        Create_BD = CreateWindow(L"BUTTON", L"Создание БД", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 350, 450, 120, 20, Otdel_kadro, reinterpret_cast <HMENU>(ID_Create_BD), NULL, NULL);
        Save_BD = CreateWindow(L"BUTTON", L"Сохраненные БД", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 350, 480, 120, 20, Otdel_kadro, reinterpret_cast <HMENU>(ID_Save_BD), NULL, NULL);
        Exit = CreateWindow(L"BUTTON", L"Выход", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 420, 620, 50, 20, Otdel_kadro, reinterpret_cast <HMENU>(ID_Exit), NULL, NULL);
        break;
 
        //Событие кнопки
    case WM_COMMAND:
    {
        switch (LOWORD(wParam))
        {
        case ID_Create_BD:
        {
 
// незнаю что тут дожно быть?
        }
        break;
        case ID_Save_BD:
        {
// незнаю что тут дожно быть?
        }
        break;
        case ID_Exit:
        {
            if (MessageBox(Otdel_kadro, L"Вы уверены хатите выйти", L"Выход", MB_YESNO) == IDYES)
                DestroyWindow(Otdel_kadro);
        }
        break;
        }
    }
    case WM_DESTROY: 
        PostQuitMessage(0); 
        break;
    }
    return DefWindowProc(Otdel_kadro, Message, wParam, lParam);
}

// Пербатание собщение у дочерний оно:
LONG CALLBACK CallWindowProcA(WNDPROC hwnd, HWND Create_BD, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_DESTROY:
        PostQuitMessage(0);
    break;
 
    }
    return DefWindowProc(Create_BD, message, wParam, lParam);
}
//Дочерное окно:
int WINAPI CREATEBD (HINSTANCE hInstance, HINSTANCE hPrev, HWND ChildsWindows, LPSTR szCmdLine, int nShowCmd)
{
    WNDCLASSEX Class_registration = { 0 };
    Class_registration.cbSize = sizeof(WNDCLASSEX);
    Class_registration.style = CS_HREDRAW | CS_VREDRAW | WS_CHILD;
    Class_registration.lpfnWndProc = (HBRUSH)CallWindowProcA;
    Class_registration.cbClsExtra = 0;
    Class_registration.cbWndExtra = 0;
    Class_registration.hInstance = hInstance;
    Class_registration.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    Class_registration.lpszClassName = L"MyClacc";
 
    if (!RegisterClassEx(&Class_registration))
        return 1;
    HWND Create_BD = CreateWindow(L"MyClass", L"Create BD", WS_OVERLAPPEDWINDOW | WS_CHILD, 500, 300, 500, 700, ChildsWindows, NULL, hInstance, NULL);
    if (!Create_BD)
        //return 2
        DestroyWindow(Create_BD);
    MSG message = { 0 };
    while (GetMessage(&message, 0, 0, 0))
    {
        TranslateMessage(&message);
        DispatchMessage(&message);
    }
    return message.wParam;
 
}
 
// Родильское окно 
 
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam);
 
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int nShowCmd)
{
 
    WNDCLASSEX Class_registration = { 0 };
    Class_registration.cbSize = sizeof(WNDCLASSEX);
    Class_registration.style = CS_HREDRAW | CS_VREDRAW;
    Class_registration.lpfnWndProc = WndProc;
    Class_registration.cbClsExtra = 0;
    Class_registration.cbWndExtra = 0;
    Class_registration.hInstance = hInst;
    Class_registration.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    Class_registration.lpszClassName = L"[lexpenz.com] Win32.";
    if (!RegisterClassEx(&Class_registration))
        return 1;
    HWND hwnd = CreateWindow(L"[lexpenz.com] Win32.", L"Otdel kadro Win32.", WS_OVERLAPPEDWINDOW, 500, 300, 500, 700, NULL, NULL, hInst, NULL);
    if (!hwnd)
        return 2;
    ShowWindow(hwnd, nShowCmd);
    UpdateWindow(hwnd);
    MSG msg = { 0 };
    while (GetMessage(&msg, 0, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
    }
 
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
    switch (Message)
    {
    case WM_CREATE:
 
        //Создание одельные вкладки
        HWND Create_BD, Save_BD, Exit;
        Create_BD = CreateWindow(L"BUTTON", L"Создание БД", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 350, 450, 120, 20, hwnd, reinterpret_cast <HMENU>(ID_Create_BD), NULL, NULL);
        Save_BD = CreateWindow(L"BUTTON", L"Сохраненные БД", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 350, 480, 120, 20, hwnd, reinterpret_cast <HMENU>(ID_Save_BD), NULL, NULL);
        Exit = CreateWindow(L"BUTTON", L"Выход", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, 420, 620, 50, 20, hwnd, reinterpret_cast <HMENU>(ID_Exit), NULL, NULL);
        break;
 
        //Событие кнопки
    case WM_COMMAND:
    {
        switch (LOWORD(wParam))
        {
        case ID_Create_BD:
        {
 
                // Как ставить дочерное окно суда??
        }
        break;
        case ID_Save_BD:
        {
                        //?????????????
        }
        break;
        case ID_Exit:
        {
            if (MessageBox(hwnd, L"Вы уверены хатите выйти", L"Выход", MB_YESNO) == IDYES)
                DestroyWindow(hwnd);
        }
        break;
        }
    }
    case WM_DESTROY: 
        PostQuitMessage(0); 
        break;
    }
    return DefWindowProc(hwnd, Message, wParam, lParam);
}

#include <windows.h>
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    switch(Message) {
        case WM_RBUTTONDOWN:
        {
            MessageBox(hwnd, " Win32 API ", "Window",
                MB_OK|MB_ICONINFORMATION);
        }; 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; /* A properties struct of our window */
    HWND hwnd; /* A 'HANDLE', hence the H, or a pointer to our window */
    MSG msg; /* A temporary location for all messages */
    memset(&wc,0,sizeof(wc));
    wc.cbSize        = sizeof(WNDCLASSEX);
    wc.lpfnWndProc   = WndProc; /* This is where we will send messages to */
    wc.hInstance     = hInstance;
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+2);
    wc.lpszClassName = "WindowClass";
    wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION); /* Load a standard icon */
    wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION); /* use the name "A" to use the project icon */
    if(!RegisterClassEx(&wc)) {
        MessageBox(NULL, "Window Registration Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
        return 0;
    }
hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,"WindowClass","Ìàñëîâà Àëèíà ÈÑÈÏ 19-3",WS_VISIBLE|WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, /* x */
        CW_USEDEFAULT, /* y */
        640, /* width */
        480, /* height */
        NULL,NULL,hInstance,NULL);
if(hwnd == NULL) {
        MessageBox(NULL, "Window Creation Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);
        return 0;
}
 
    
    while(GetMessage(&msg, NULL, 0, 0) > 0) { /* If no error is received... */
        TranslateMessage(&msg); /* Translate key codes to chars if present */
        DispatchMessage(&msg); /* Send it to WndProc */
    }
    return msg.wParam;
}