While this app doesn't require any manual installation, it does use menu items that you set up in Shopify's Navigation system. Please follow the step-by-step instructions in this short screencast to set up menu items and collections then refresh to see them in the category list.
All settings are entirely optional. You should not have to change or configure any of the default settings to make the app show on your site. If you would like to change the look and feel of the app, please feel free to mess with the settings. Each time you change a setting, please then refresh the menu. The refresh operation publishes the saved changes to your storefront. Then simply open up the storefront in your browser and refresh the page (Ctrl+F5 on PC, or Cmd-R on Mac).
If you want to temporarily disable the menu, you can uncheck the Show navigation menu on hover/click options then refresh the menu.