Start with the headset turned off, and the bluetooth radio of the device you want to pair the headset to, turned on. Then, press and hold the headset's power button until the led flashes rapidly. It is indicating is in pairing mode. Now, make your device search for new devices, and select the BH-100 from the list. If a passkey (or PIN, or pairing code) is requested, enter '0000' (four zeros).
If your headset's user guide happens to be missing, download it from
this location, if you want.
Hope it works for you.
Cheers!
Carlos