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First on the plugin's option page, choose which widget area(s) you want to apply the scroller effect. Also provide a fixed height for the scrolling panels. You can leave it blank if you have specified a fixed height in your theme's stylesheet.

Goto the Widgets page and add a couple of widgets to that widget area. Use the Area Scroller :: Divider widget to divide the widgets in multiple panels.

Voila! That was it. The default skin provided with the plugin shows the next & prev buttons beside the widget area. To arrange the widgets in multiple columns, I'm using the Widgets in Columns plugin.