Go to the screen you want to capture. For example, you can go to WhatsApp and open the conversation.
Press and hold the Volume Down and Power buttons at the same time. Continue to hold the button until you hear a camera shutter or you see a notification. This is the method of combination of keys Android. To use another key combination, hold down the power buttons and the Home button simultaneously until you see a notification or hear a shutter sound. That's all! You have successfully made a screen capture on your HTC desire 601.
View the screenshot in your notification bar or from the Gallery application.