Steps for Creating A MDI Form:
1. Build a new form and set IsMdiContainer property to true.
2. Build a child form class to add to the form.
3. Now Right click the project in the solution explorer.
4. Choose add and then select the Windows Form.
5. Build a new child form object and set the MdiParent property to the parent form.
6. Invoke the child forms to Show method.
7. Write the coding below to build the child form in an event handler.
Dim childForm As New ChildFormClass()
childForm.MdiParent = parentForm
childForm.Show()