Got the book, but haven't read it yet or looked at the videos. I'm trying to come up with a strategy that makes sense.
If you are not going to get together with a transition instructor,
read the book and look at the videos is a strategy that makes sense
As already mentioned, Avidyne has a very recent series from basics to advanced. Excellent stuff. Yes, there is some marketing involved ut the marketing is to show Garmin folks how to do things. They are still doing them via live webinar so you can even ask questions and get the benefit of questions from others. Go to the site and sign up.
And, as always, Martin's explanations are superb and as others mentioned, he just did a transition.
The big picture is understanding that Avidyne and Garmin use different logic. A GNS to GTN transition is relatively easy for most because, flow-wise, Garmin is Garmin is Garmin. The IFD will do everything your 530 can - more actually; it's newer after all - but how to do it can be very different. So part of your self-training should include using the IFD emulator to run scenarios of things you have actually done with the GNS, both common and uncommon.
That last part is pretty much the strategy I used. I don't fly with an IFD but I periodically do recurrent training in an airplane with one, so I felt I needed had to know the system fairly well. The result was, as a COVID stay-at-home project, a series of videos (three at this point) comparing Garmin navigators with the IFD: holding at a waypoint a distance from a fix (which I think was referred although not by name in one of the Avidyne webinars), creating a user waypoint, and intercepting an assigned radial or course to a fix. Not sure how helpful they are to others but the YouTube playlist is here:
https://www.youtube.com/playlist?list=PLmolGJZEeVA4ivopGnB7nG4CckULY22QY