BeamTheme Addons is a site specific plugin that adds features and functionality to sites using Beam WordPress Theme.
After installation, Beam Recent Posts Widget will show up in the Widgets panel. Drag it to Sidebar to activate it.
Once you do that, your BeamTheme Recent Post will show up like on the image below.
Please use Regenerate Thumbnails plugin in case your images are not showing as square 80×80 pixels.