While doing an activity do i need to long press the power button to lock the screen or not? since i tried to quick press the power button nothing happens
Just press the button. Top of the screen will display a message saying Touchscreen Locked
Yes but how do you then unlock it ?!!!!
If it is locked just press the power button again to unlock it. It is a toggle action, on/off
Also note that if screen capture is on (system, display, Screen capture) then pressing the power button will take a screen shot instead of locking the display