Galaxy S6 :: Cannot Capture Screenshot On Phone

According to the information that I had read so far. There are 2 ways to capture screenshot:

1. Press the power button & Home button together.

2. Use the Motion & gestures, palm swipe to capture method.

Method 2 so far work for me. But it's a little tricky because sometimes the screen register my palm swipe as finger swipe and it moves the page...

I prefer the use of physical button. But I couldn't figure how to use the method 1. Whenever I try to hold down the power and home button together (for about 2 seconds), it's either launch Google Now or it bring me back to the home screen...