I`m a newbie at Bluetooth Low Energy and Nordic Chips. I bought a DK for the nRF51822. I would like to set I/O pins over android and iOS application. 1.So what application is the best to start with? 2.Or is there already an app which light up a led or something with a button click? 3.What code I need to load on the nRF51822? 4.If I need to write my own Service, how should i do that in function with setting GPIO?