The documentation in Ren'Py regarding 'creator-defined displayable' is very straightforward to me. The creator-defined displayable is supposed to be a canvas to allow the programmer to draw anything. If you don't understand how to program your breakout game with Pygame, you absolutely will not do it in Ren'Py with the creator-defined displayable. If you don't understand the example in the documentation, you absolutely will not achieve your aim in Ren'Py.
I won't hold your hand in the details of getting this done. I will leave these hints to you:
1. Figure out how to draw a simple static (a non-moving, non-changing) colored square with the creator-defined displayable.
2. Figure out how to animate that square (move it, change size, change color, change opacity)
3. You should be able to draw multiple objects onto your displayable
4. Program a breakout game with Pygame, not Ren'Py. This is so that you understand the principles of programming and drawing a game to a screen
5. You should be able to port that logic of the breakout game onto Ren'Py's creator-defined displayable.