Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority.
Sorry to hear you’re having trouble.
What model kindle do you have?
No kindle fire model has an actual "anti glare" setting.
Kindle fires, in general, do not work well in direct sunlight.
You can adjust the brightness up all the way which may help somewhat though - touch your finger at the top of the screen and slide down about 2 inches, this brings up the quick settings toolbar, and there you'll see display/brightness, which then has a slider bar to turn it all the way up (as well as disable auto brightness).
Beyond that, you'd need to purchase a special anti-glare screen cover/protector: http://amzn.to/1NOw4CA