Proceed as follows if you want to remove uploaded files from study lists:
Go to your study list and to the external content. Click on the delete icon (trash can). Your file is then no longer in the study list.
Alternative:
Open the "My content" tab (see marker A in the screenshot). Click on the study list icon next to the document you want to delete.
A pop-up window will open. Scroll to the study list from which you want to remove the file. Click on the "Remove" button.
Done! π
Note:
Your file will then still be available in your own content. If you want to permanently delete a file not only from a learning list but also from your own content, click on "Own content" and on the right on the three dots, then on Delete.