If you have completed the carousel widget installation, but when using the carousel the image stack vertically. This mean you may not have installed the carousel in the page layout you are using. Carousel widget requires to be install in specific page layout. If you complete the installation for Tall Header, but you are using Short Header Page Layout the widget will not work. Simply repeat the installation of the script code for all the page layout you are using. Republish your site and the widget will than start to work.