When you have existing content in your Wordpress installation, activating your theme will most likely make your site look a little weird. The reason for that are Widgets that are assigned to default positions that don't fit with the theme. We can improve that by assigning them to better positions available in our theme.
Navigate to Appearance » Widgets. As a first step, you might want to drag most widgets to the Disabled Widgets position. In our example, those widgets are located in the Search position. We'll remove all widgets here except for the actual Search widget.
Check your site, it should look less cluttered now. From this state on you can now assign widgets to the several available positions in your theme. For an overview of all widget positions in your theme, check the Home » Widget Positions page of the theme in our online demo.