Day to day I'm seeing many questions which say:
Screensaver/lock doesn't work.
Screensaver doesn't require password after waking or doesn't lock the screen.
Can not exit screensaver / nothing works after pressing key or moving mouse.
and many many more not specific with gnome-screensaver only but also with xscreensaver.
So how to make a simple, fast and lightweight screensaver which locks the screen after given time and requires the password in order to continue?
In addition to my answer, I request to others who have other answer to share here.. :)