Graphical Problem !!!!! Please Help ?

The Unity version looks like it has too much ambient light and no light maps. Re-bake light maps in Unity using Beast. Also, it looks like the tarp is glitched because it's a one-sided open object and backface culling is on. If you duplicate it and flip normals on one of the copies, that will let you see both sides without turning off back face culling on the shader.

In general, though- if you are new to this you shouldn't expect to be able to just drop a scene from your modeler into Unity and have it import everything and look the same as your render, there is more work that goes into making a game environment look right than there is rendering a scene with default settings in a 3D program.