C# Mdi application with child forms

I am a newbie as far as doing Windows Foirms apps and I want to develop an MDI app in C# that has a "main form" with well defined sub form sections such that when I press a button on one child form it cause the exisiting child form to be replaced with another. I looked at articles on topics such as Newing up a form instance and setting it to be the child of the parent (main form). Is ther some resource where I could learn this via a book or a tutorial online? As I a said I am a newbie. The app I have thus far has the main form open and it has the two buttons that I added. Ideally I will have the child forms reside only in a sub section of the entirte form for the application such that one part of the main form has a list box that remains on the GUI regardless of what sub (child form) I have loaded, I hope I have provided enough information to ask "my question" well enough, thanks in advance for any help.