Garmin Forerunner 50

ANT+ is not Bluetooth

The sensors just transmit, they don't know if a receiver hears them or not.

Any receiver (watch, GPS, etc) that can hear an ANT+ transmitter can be told to pair with that sender. There is no secret PIN code to enter and you can have any number of receivers listening to a sensor, so if you have a GPS and a watch, the HRM strap can send to both at the very same time.

The Forerunner 50 can listen to a HRM (heart rate monitor strap), a shoe pod, and and HSC-10 bike speed/cadence sensor.

To reboot

you could pop the battery out, which is about a 20 minute affair, you really only want to do this if the battery dies

or,

hold down the mode, view, and start/stop buttons until the watch reboots.

To pair with sensors

(page 25 in manual) you could uselessly try over and over to follow the instructions - put in Train mode then hold start/stop which does nothing

or,

1. get ALL sensors ready and in range - put on the heart rate strap, and put the shoe pod and bike speed sensor in range, put fresh batteries in everything
2. do a reboot,
3. put in Train mode (push/release Mode button until TRAIN appears)
4. hold down Stop/Start and when Hold/Set appears continue holding down
5. this puts it in a mode where you walk through each setting, adjusting or moving on as needed.
   1. Units Mi/Km
   2. Gender F/M
   3. Weight
   4. and so on until finally the sensor indicators blink: bike,heart,shoe and if the sensors are nearby and ready then it will pair with them