How to work on MDI form container

hi
i am studying c# and i have atask to do
could u plz help me do it
my task is to
make a new Notepad but with MDI
there should be 2 forms, the 1st is the main form that has a menu with (New-open-Save) at least (add "save as" & the window menu if possible)
use the open & save dialogs to make things easier
open loads a text file & adds its contents to the textbox or richtextbox in a new window (that is a child to the main window)
the save menu button saves the file in the selected path
*"Save as" asks for the path but "save" saves on the previously selected path, if non was selected it acts as "save as"
i really wish to know how i could do it
bye