For the free AVRT thing, you need to go to the AVRT website. There are copyright things and SR's policy about linking to commercial websites, so there you go. Google knows where to find it.
For AVRT threads, you can't do better than the one on the front page here called AVRT Discussion, the one now currently in Part 5, which means we are now up to over 2200 posts on it. There is a link to page one in the same thread.
There is another thread,
AVRT Explained that I think is not bad. But that's just me.
So, JuneBugApril, jump in anytime. Looking forward to your comments and participation too.