Step 1: Change the volume
The Kindle Fire only has one button, the power button. Tap it to turn the Kindle on and tap it again to put it to sleep. Longer presses actually turn it off.
That's great, but no volume buttons? Nope, it's stuck in the settings menu. To get to those, tap the little gear on top. Now you can change the volume by selecting "Volume" and sliding the volume control.