It's called widgeds, on native android device you would scrool on menu to the right and select the widget. With samsung and it's touchwiz interface I don't know.
But look up for WIDGETS.
It varies a little from one phone and OS version to another, but long-pressing a blank part of the Home screen may give the option to access the widget locker.
Please refer to the above answers. Long pressing on any blank space in your home screen will give you the option to add widgets. Question answered. Thread closed.