The Kestrel 2700 is always advertising its Bluetooth signal so you just need to turn it on. You should NOT pair the 2700 directly to your device’s main Bluetooth screen. First, make sure Bluetooth is turned on on the mobile device. You would then just need to open the Kestrel LiNK Ballistics app and go to Connect Device. Your unit with serial should be showing on the screen, press it to start the connection.