My iphone's screen won't tilt when i turn the phone around?

I'm not sure if i did something wrong with the settings or wat?

Click the home screen button twice very fast ( the circle button with the square in it ) then slide your finger to go to the left on the bottom screen that will pop up then select the option that lets the screen tilt. If you have an older iphone you can change this in the settings

1) Double tap home button, a bar should pop up at the bottom of your screen.
2) Swipe screen to the left.
3) There should be a music symbol on the right, play button in the middle, and an arrow going in a loop on the left.
4) If the arrow loop has a lock in the middle, click the arrow again. The lock will go off and you will be able to tilt again.

Hope this helps