Were you looking for help? If you want people to reply to your topic, you can't lock it before anyone posts.
As for how to "Learn" to put your thumb in, you have to do it the same way the rest of us did, PRACTICE.
Since you are in the Dallas/Ft Worth area, you have incredible resources available to you. I took lessons from Rod and Theresa Ross when they were still in this area(Central Valley of California) and it was money well spent. Rod might not be available for private lessons now, but Theresa probably is and she is a fantastic coach.