The manual we used has long since departed. I don’t remember who the author or publisher were. I don’t think it was VW.
The older VWs are a blast to work on because they are so simple. The simplicity is a great way to into a newbie to auto mechanics.
The book I used a lot was “How to Keep Your Volkswagen Alive: A Manual of Step by Step Procedures for the Compleat Idiot”, by John Muir. It was illustrated with drawings, very few photographs, and it told you in plain language how to do just about anything on an air-cooled VW. Plenty of asides and digressions, too, making it fun to read. I still have a copy of the 17th edition around; my earlier ones got worn out.
You’re right about old VWs being good cars to learn basic mechanicking on. That ‘66 was my first car, and I knew very little about auto maintenance and repair when I got it.