Start, Pause and Game Over screens

I am trying to make a platform game using Box2D and LibGDX. I wonder how you handle Pause, Start and Game Over screens.

By Start screen, I mean this: When the game begins, I start it as paused, so the player can be ready for moving the character. I do this by rendering a black image with alpha= 0.5f, and a Scene2D label “Touch the screen to begin”.
I don’t have a Pause screen yet lol.
Game Over screen is also a black image with 0.5 alpha value and a label saying “Game Over”. I haven’t put any buttons for restart or go to menu, but I am planning to do.

But like I said, I wonder how you handle these kind of screens. Do you make a new class which extends Screen (those who are familiar with LibGDX should understand what I mean :)) and show that when the player pauses the game or when the game is over?

What do you do with these screens? How do you handle this?