When pairing Bluetooth devices, you need to make sure they see each other. By default, the Kindle Fire HD has Bluetooth Enabled, but it’s hidden and not broadcasting that it’s available If you are having difficulty pairing a keyboard, headset, computer, or another tablet with your Fire, follow these steps to make it visible.
Swipe down from the top of the screen to open the notification bar and tap More.
Select Wireless from the settings screen.
On the Wireless page tap Bluetooth.
This should set the Kindle Fire to be visible for two minutes so you can pair your devices. If you can’t get it set up quick enough, just click it again to give yourself another two minutes.