Most important thing for non-experts to understand is how important it is to "ask the right questions" in ML / "AI" / Stats / Data Science - and what kinds of problems naturally lend themselves to ML solutions (and which don't).
This is a great intro:
https://developers.google.com/machine-learning/problem-framing/
This is another really good high level intro i found: https://www.coursera.org/learn/data-science-course
Second most important is understanding the importance of data https://developers.google.com/machine-learning/data-prep/