How do I pause and unpause my game on the iPhone?

How do I pause my scene in Unity IOS like what method would I use to get this to happen?

I need the help on how to pause just one scene and have that scene paused for a certain amount of time

There are an infinite number of custom methods you can employ, but the easiest is setting Time.timeScale to a very low value. This is not an iOS-specific question at all, so you can easily find information about it.

Personally, I implement event handlers in all my scripts that need to have some pause/unpause functionality. When those events happen, I stop or resume behavior as desired.