sub-topic CDN Starterkit
The CDN Starterkit is rather simple to set up. You don't have to do anything until you wish to override the default Drupal Bootstrap base theme settings or provide additional custom CSS.
Read the Sub-theming parent topic.
./subtheme/css/style.css and modify the file to your liking.
Please refer to the Sub-theme Settings topic.
Override Templates and Theme Functions
Please refer to the Theme Registry topic.