如何从另一个对话框中显示对话框？

I am newbie to MFC. I have a native C++ MFC app. I want to show a dialog from main dialog. In the main dialog I am having three button (Back, Next, Cancel) respectively. On the Next button click event I am calling DoModal to show another dialog by hiding the main dialog as follows,I am newbie to MFC. I have a native C++ MFC app