When I first bought the book and subsequently the audio book from soundstrue.com in 2010 there where no workshops near where I lived. I attended the first workshop in 2012 and another in 2013 in south Germany after that option became available. In the meantime I had learned and practised the method for quite a while and with surprising results - so I wasn't really there to learn anything, more to meet "the guy". What struck me most at the time is that he cited from his audiobook almost verbatim (I had listened to it many times so I also recalled it quite well).
So IMO anyone can learn the technique just as easily from listening to the mp3 files and participating in the workshops is more of a social event, meeting of similar minded people and mingling with the "healer crowd".
The method is easy to learn - in the same way riding a motorcycle is easy to learn. You can drive and not fall over in a few hours but being a safe and able driver can take years to accomplish. Some people compare it to piano playing but I think riding is the better metaphor. A basically easy skill, but hard to perfect unless one puts in the time.
Now the big question: how do I know I am ready? There is no easy answer although I am currently working on providing one (hopefully). You will have to try it out. My first ever client was a 10 year old boy with a painful mid ear infection. I treated him for 10 minutes (after I had practised for about 6 weeks, many hours per day) and voila - it worked!
Here is a link to the official site than lists the workshops:
https://www.bengstonworkshops.com/