Welcome back to Bryce. It is difficult to answer your question about in-depth tutorials on the menu items on the Mentoring DVD. There are some but may not be the ones you’re looking for. I understand your mode of learning very well: the why is at least as important as the how.
Have a look at my website (see sig) and go to Bryce Documents. You will find a couple of things that may interest you. Under Mine PDF > Diverse you find a document that lists everything that’s on that DVD. The sub-topic Material has a 84 page PDF summing up the 17 videos by David on the DTE. Under the Video link, you find also links to the video Transcripts which are sometimes quite elaborate and are more than just transcripts.
Thanks Horo, on my way there now