No, you do not need to create a pairing between the thermometer* and your mobile device/tablet.
BrandM8 uses a newer form of Bluetooth called Bluetooth 4 or Bluetooth LE which does not require pairing. It is not the same Bluetooth that you may be used to when using a headset or hands-free connection in your car.
Once you have powered on your thermometer, start a checklist with a temperature question and a connection will be made automatically.
* Temperature probes require integration and must be supported. Manual pairing can cause connection problems. Manual pairing should be removed.