How to use 1. Please choose the Parent iPhone, and you can start to decide the 2-character channel number and please tap the Start button. (Please enter you like number 2.) 2. In the Child iPhone, start by setting the 2-character channel number that you set in the Master iPhone and please tap the Start button. This app can interlock iPhone of three sets. * If the application does not start camera, please check the following. Settings -> Privacy -> Camera-> Pair is on.