如何使用核心蓝牙sdk扫描蓝牙设备?

I'm currently creating an iPhone app (Xcode 6.2, IOS 8.2) that could use Bluetooth devices! Main goal of this application is only search the available bluetooth devices and whenever you go to out of range from bluetooth devices one alert message pop up.and when ever you come in range automatically connected.I'm currently creating an iPhone app (Xcode 6.2