How To Add Launch Screen File in Xcode for iPhone 6 Optimization?

I'd like to know how to add a Launch File in Xcode for iPhone 6 optimization?

On Xcode, when you click on NEW -> File -> User Interface -> Launch Screen a xib file is created in project. My question is how to "fill the blanks" and make that file (xib) useful for iPhone 6 optimization?

Apple requires it for iPhone 6 optimizations: iPhone 6 optimization Launch Images

Apple says,

"You use a launch XIB or storyboard file to indicate that your app runs on iPhone 6 Plus or iPhone 6."

Here's another reference of what I am talking about: Xcode: Using a Launch Image File

How to create that XIB / Storyboard to indicate that my app runs on iPhone 6 / 6+? Thanks in advance!