Everyone learns in different ways. Some people like to listen to an instructor discuss a topic, while others prefer to read the materials and/or watch a video. To accommodate different learning styles this site has both podcasts and text versions of the same content. The pdf version often contains charts that you may wish to review. Various tools are also included to expand your understanding of the content such as links and demos. Other tools, such as the Quiz, test your understanding of the material. Try the various tools and see which ones help you master the content.