Screen capture on Huawei P9?

Is the screen capture at Huawei P9 possible? If I press the power button and volume louder it does not funzt.

For the two keys you need a lot of feeling and have to try it more often, until you get the trick out. Really at the same time and short press.

You've probably solved the problem long ago, although it's not working here, but usually you take a screenshot by tapping twice on the screen with the knuckle of a finger, at least that's what I do