1. Read more about Wikipedia, Wikimedia Projects, and Wiki Education.
Read the fundamental principles of Wikipedia to gain an understanding of its five guiding principles. Check out the full list of the Wikimedia Foundation's projects, which includes Wikidata and WikiCommons. And learn more about Wiki Education, the "spin-off" organization of the Wikimedia Foundation that supports university instructors using Wikipedia in the classroom.
2. Learn how to read Wikipedia more critically: without ever making an edit.
Have you ever checked a Wikipedia article's history or talk pages? Did you know that Wikipedia content is assessed? You can find some of the most highly assessed, and the criteria for assessment, on the "Featured Articles" page.
3. Try self-paced Wiki Education training (see below).
Wiki Education's Training Libraries offers self-paced training. While these training modules support the Wiki Education program, they are available for free to all with no account required. Many of these modules become part of the students' training for learning Wikipedia. For example, WR120: Language and Technology.
Two starting points for the absolute beginner are: