I have a new Sass course that will be published soon. It covers Sass and Compass and shows you how to use some of the programming techniques that are available to you with Sass.
The course includes about 2.5 hours of video content. This is one of the lessons where I explain how Sass Lists work. I use the Sassmeister website in this video, which is a great place to play with Sass code and see immediately the CSS that is produces.
If you would like to follow along with the video, you can use this link: Lesson Gist