Autofocus on Tamron 200-500?

So I got a Tamron 200-500 today for my Nikon D3200 but I can't figure out how to turn the autofocus on. Any help would be great.

The Tamron 200-500mm lens does not have the autofocus motor built into the lens itself, and therefore can't autofocus on your D3200.

Does it have an internal motor?

Only motorised lenses autofocus with the D3200, if there's no AF/MF switch on the barrel, there's no autofocus to turn on.

If you mean this lens
http://www.bhphotovideo.com/...Di_LD.html
clicking on the Overview tab, at the bottom of the big description it says:
"The lens has autofocus capability however because it does not have a built-in AF motor, AF will not function with any camera that requires a motor in the lens for autofocus."

The D3200 requires a motor in the lens for autofocus.

If you insist on AF then you will have to return the lens if you can and get a refund. If this isn't possible, you could sell it, but you might make a loss on it. Otherwise now is a good opportunity to learn how to use manual focus. It could serve you in good stead one day…

That lens does not autofocus with your camera. You will have to either manually focus it or return the lens to the store.