Switch off your bluetooth device and switch off your cell phone,
Switch on your cell phone and then open bluetooth and make sure it's active and is not in hidden mode.
Now make sure that the bluetooth is fully charged and then switch it on.
Search for devices from your cell phone , use the pair option in bluetooth connectivity , and add a new pair or create a new pair.
Then the phone will search for the bluetooth and will detect it , and since this is the first time it will ask you for a pass code , you need to enter default 0000 and then select ok and then the bluetooth device will be paired and hence now you can use bluetooth.