How to create MDI application (not use appwizard)

[niponph]

i would like to know how to create MDI application by not using appwizard
i have declare class following code below

class CWin : public CMDIFrameWnd{
public:
CWin();
~CWin();
};
class CWinchild : public CMDIChildWnd{
public:
CWinchild();
~CWinchild();
};
CWin::CWin(){
Create(NULL,"Surface Reconstuction Program",WS_OVERLAPPEDWINDOW|WS_MAXIMIZE,CRect(0,0,800,600),NULL,MAKEINTRESOURCE(IDR_MENU));
}
BOOL CApp::InitInstance(){
m_pMainWnd=new CWin();
m_pMainWnd->ShowWindow(SW_SHOWMAXIMIZED);
m_pMainWnd->UpdateWindow();
return TRUE;
}
class CApp : public CWinApp{
public:
virtual BOOL InitInstance();
};
CApp theapp;

How can i do next ?
or Do you have code sample for study?

thanks you very much