Turn on the headphones. In the Quick Settings on phone, tap the Bluetooth icon for switching it on. You can go to the settings menu, choose connections and then Bluetooth too. Tap scan and check the connections available. Based on the instructions given along with Bluetooth earphones with mic or any other headphones, pair them with your phone. If there comes a confirm pop up, accept the pair option. You can also connect headphones to phone via aux or Wi-fi network.