Widget is a fancy name for a small box of content that you can add, move or delete in your sidebar, front page and other places on your website, depending on your theme.
Just to the right of the black navigation column are the various widgets that are available, and to the right of those are the widget areas.
Clicking on an available widget with display a list of all the widget area, simply choose which one you want to add the widget to and click ‘Add Widget’.
Another way is to open the widget area by click on it and then drag the widget you want over on to it.
Each widget will have different options you can select, or areas that you can input your own text.