Before starting iOS integration, you should note that there are two different push pathways provided by Apple:
We recommend starting with the iOS Development platform, then moving on to the iOS Distribution platform when you're ready for an Ad-Hoc Distribution or submission to the App Store.
Add an iOS Development Platform to your Application.
Create Push SSL Certificates (.PEM File) via Apple's Provisioning Portal.
Upload the .PEM File to the Mobile App Developer Console.
Download the iOS SDK (Push IO Manager) and include it in your Project.
Download the pushio_config_debug.json (Development) file from the Mobile App Developer Console and include it in your project.
Add optional frameworks (CoreLocation) to your project.
Add necessary code to instantiate the Push IO Manager in your application.
Run your push-enabled application and send your first push!
Once an iOS Development Platform has been successfully configured, configure an iOS Distribution Platform so you can push to Ad-Hoc or App Store versions of your application!