Sentri allows you to connect and control all your smart devices from one simple interface. To start, you will need to have either an iOS/Android app. Go to the 'Devices' page and ...
Click on 'Add new device'. Make sure that your mobile phone is connected to the same network as your other smart devices (usually the same wireless network).
If your mobile phone is connected to the same network as your Philip Hue light bulbs or Belkin WeMo devices, Sentri should automatically detect them. Connect your Nest by logging into your Nest account