You can use the Assistant Menu feature as well to take the screenshot. Goto Settings > Search for the Assistant Menu > Make it ON. Now the Assistant Menu is enabled in the device. In the Assistant menu you can see the "Screenshots" option to take the screen capture. :)
1. Get the app or screen that you want to capture ready to go.
2. Press and hold the home button and the power button at the same time. It can be a bit of a stretch on these larger phones, but it works just fine. You'll hear the camera shutter sound, along with a short flashing animation, and that's how you know you're good to go.
3. You'll now be able to see the screenshot in the Gallery app,
