Xamarin Forms Bluetooth

Hi,
I am trying to create a Portable Class library Xamarin Form project in which I need to use Bluetooth of the device to communicate with HC-05 Bluetooth module using serial communication. I want the code to be cross-platform. Can anybody please guide me step by step how can I do a single coding for both Android and iOS platform in Xamarin Forms. I don't want to opt for platform-specific coding. Thanks in advance