Since Apple will be storing our high scores and achievements on their centralized servers, we need to communicate to Apple that we need Game Center for our app. The first step is to create a record for our app on the iTunes Connect website. Follow these steps to create an iTunes Connect record:
In a web browser, navigate to http://itunesconnect.apple.com.
Sign in with your Apple developer account information.
When you reach the iTunes Connect dashboard, click on the My Apps icon.
Towards the upper left, click on the + symbol and select New iOS App, as shown here:
In the subsequent dialogue, locate the link at the bottom that says Register a new bundle ID on the Developer Portal. Click this link to create a bundle ID for your app.
You will arrive on a page titled Registering an App ID. This page may appear overwhelming at first, but you only need to fill out two fields. First, enter the name of your app in the App Description section.
Scroll down to the App...