How to implement page switching?

I'm a fresh man, I want to implement an application with many pages , for examples, when the application first runs, there is 2 buttons, when I press one button, turn to the other page, with 3 different buttons. All these pages are created in Qt Designer, and they are ".ui"files.

I don't know how to implement this page switching , some one help me , thanks a lot

try QStackedWidget and switch its pages using setCurrentIndex(int)