My iPhone 6 won't turn on

It is fully charged. I went to turn it on and it's just a black screen. I have held down every button and nothing is working. I'm really confused because I just used my phone and now it's refusing to turn on! How can I turn this thing on?

REMOVE THE BATTERY, WAIT 2 MINUTES, PUT IT BACK, THEN TRY AGAIN TO TURN IT ON.

I hope that works!