Trying to understand .xib splash and Unity!?

Hi, I am really hoping that someone can clarify or shed some light on the .xib splash screen feature in Unity.

I have tried to use this feature, which i mean is absolutely perfect, if I just understood it.

Here is how I "think" it is working.

1. I create a new XCode project (singleview), saving it somewhere outside the asset folder, in which I create a new View and calling this splash.xib.

2. I then design the splashscreen as I would like it, importing the images I want,...

Trying to understand .xib splash and Unity!?