How can I make a loading screen(Needed in DETAIL)

Ok my game has a pre-release But before they get the game I need to have a loading screen because when I compiled it the map had so many things in it it took for ever to walk it was like ***

it was running at 1 FPS/Frames Per

*** So I want it so I can have a loading screen with a picture and a loading bar that has animation How do you do the script and how do you make the animation unless the animation is in the script!?!?!?!?!?!

I’m not sure about the picture, but here is some code from my project while I was learning Unity:

			float percentLoaded = Application.GetStreamProgressForLevel(1) * 100;
			GUI.Box (new Rect(playButton), "Loading..." + percentLoaded.ToString ("f0") + "% Loaded");