Hi , I'm new to Unity 5.0.0. I trying to make a simple robot game.
The only thing I'm having trouble is skybox.
I went to free assets store down loaded skybox.

Then press the imput waited when done
the chooses apeared in project box.

I tried using terrain texture to add the image.
2 grey boxes open to the left.
Move it over but no add button appeared.
What did I do wrong.
I have Windows 10 64 bit
hp computer laptop