Website recommended by Stephen Downes:

Finding Open Content Tutorial

OER Africa, Feb 01, 2019

As the website says, "The tutorial is designed to offer a simple, quick way to acquire skills necessary to search for open content, decipher Creative Commons rights and permissions and evaluate the usefulness of open content." It provides search strategies for finding open materials on Google, YouTube and Creative Commons, as well as a section on evaluating open resources.

For more informtion visit this link https://www.oerafrica.org/book/welcome