How to implement OnDraw() and Serialize()

Hi, everyone,

I am a newbie to MFC and currently working on a project that needs to
display file data and save opened files onto storage. After I created a MDI
project and the default code had given me the basic frames and
functionalities. When I open a file, a child window is opened with the
filename on top. But no data is displayed. After reading the MSDN help
information, I realize that I need to override OnDraw() method of CView, and
Serialize() method of CDocument. Can anyone give me some example code
implementing these two methods so to display and save file data?
The example code in MSDN docs doesn't seem to be of much help. In OnDraw(),
we get the file by calling GetDocument(), then what should we do to display
the data in the document?
In Serialize(), we need to add storing code and loading code, but what
should they be?

Thanks for your help.