I am new to drupal and a bit stuck. I am about to make a bootstrap subtheme. I have downloaded the drupal 8 folder from drupal's website and that is what I'm using. I have tried to follow tutorials on creating subthemes, all of them mentioning the CDN folder inside themes/bootstrap/starterkits directory. However, in my case, I can't locate it anywhere. Is there a way of manually downloading and pasting the folder from another source? Any help will be appreciated!
My themes/bootstrap/starterkits
In order to extend your theme, you must create a fresh theme and then, in your theme.info.yml extend the base theme
core: 8.x
type: theme
base theme: bootstrap //or your base theme
To create a new theme from scratch, this article will help you
https://www.drupal.org/docs/theming-drupal/how-to-create-a-basic-drupal-8-theme
The tutorials you are following is out of date. According to this issue, all starterkits have been replaced with a single generic starterkit, which is the folder THEMENAME you see.
Now, you can follow the updated tutorial here.
