Solution Recipes: Support Files are just set of files that you will need to follow our solution recipes which will help you cover one aspect of using the Extension. Each of the solution recipe include a PDF file which will guide you in completing the solution recipe using the files in the Support Files folder.
For example the "Customizing Menu Writer Menus" solution recipe will help you set different background images for the menu buttons.
You should not have to install any additional extension in DW as long as you have MW installed and a site defined. Some of these solution recipes might require a php site and others could be applied to static site.
let me know if you still have any other questions.