Next, we will need to install our new theme by navigating to /admin/appearance and locating our new theme named Twiggy under the Uninstalled themes section. Click on the Install and set as default link to install our new theme.
Our new theme folder structure should look like the following:

Based on the content that we may have added to our Drupal 8 instance, we should at least have an unstyled blank slate from which to work with once we begin learning Twig.