Check out this video from Flame Guitars on installing a JLD Bridge Doctor. As David says, this video isn’t a “How to” video as such but more of a general overview of how the device works.
There’s a great part, around 6 minutes, where David tightens the device; you can clearly see the bridge rotate and the bellying top flatten, in real time!
This particular installation in a 1970’s Guild F40 which was showing all of the signs of a bellying top. There’s an extended video of all the work David did to this acoustic guitar; a neck reset, JLD Bridge Doctor install and an entire re-fret.
You can find out more about the JLD Bridge Doctor HERE