HTC One M8 for Windows - Manual (Page 48)

Taking a screenshot
See something on your screen that you want to save or share? It's easy to
take a picture of the screen.
Press POWER and VOLUME UP at the same time. The screen is saved in
the Screenshots album in the Photos app.
Switching between apps
Your phone can remember apps you've used most recently, and there's an
easy way to switch between them.
1. Press and hold to see what apps you've used recently.
2. Swipe left or right across the screen, and then tap the one you want
to use.
You won't see recently used apps if you've closed apps by tapping
or shut off the phone.
48 Your first week with your new phone