I can't find how to use a UIViewController to start my app, help please!

I can't find how to use a UIViewController to start my app.

I saw some tutorials but i'm not getting it at all, i don't know how to get a UIViewController to start the app and put the unity view inside a TabBar button, so i can have two more views. of native cocoa UI.

I don't want any kind ot interaction between Unity and the cocoa UI more than the Unity pause, it's just that i have to make two sections more in my app that i don't have to do inside Unity.

Help please, i'm wasting a lot of time trying to find info for this and i can't seem to find it.

Cheers.