How can i program in C#, to open new Forms in the same window?

How can i program in C#, to open new Forms in the same window, when clicking on a button?

Example: I need open Form2, Form3, Form4, without open a new windows, but, in the same window, how i make, please? I need the code in C#!

I want, using this method ''new MyOtherForm'', and a complete code, please i need help!!

new MyOtherForm().ShowDialog();

new MyOtherForm().Show();