How to reset Unity 3D

Hello,
how do i get my standard settings back?
I can’t see anything. The scene with the sky isn’t there anymore, idk why. (Picture)
I put in 2 Pics. One the way it looks for me and one it should usually look.
Thanks alot.


You are looking at the scene tab rather than the game tab.

You can revert your layout at any time by pressing the ‘Layout’ button in the upper-right and selecting default.

Thank you for your answer.
Now i have this picture. How do i get the scene with the blue sky back? I really would like from start.
Where can i set the light, so i can see something?

Assign a skybox in the Lighting Window/tab