Database theory (normalization) for beginners (adult education, MS Access)
Based on the comments, the minimum for theory and technical is how the nomenclature of MS Access relates to Excel.

If they've been doing everything in Excel anyway, they've developed habits for, or against, normalization that you're not going to break in a couple days, intensive or not.

If they haven't discovered the pitfalls of redundant data in Excel, they probably won't in MS Access either. If they have, then they've already learned the lesson, and developed their own methods of "normalization."

You can bring it up, and have resources available for them to access, online in their own time, if they develop the interest in "doing it right." Otherwise, concentrate on helping them become fluent in MS Access, an hopefully reduce the calls for help you get when they don't remember how that works in two weeks.