Matt is a good place to start. For a more complete approach, there are a number of YouTube videos by Taeho Kwon on a massive screen he built. He has some great design of sleds for cutting hexagonal and diamond grids and some methods of constructing some of the more complicated kumiko patterns.
https://www.youtube.com/c/WoodArtStudio1/videos
Of course, Desmond King is probably, as far as I know, the preeminent Western authority on Kumiko. An Australian who studied Kumiko in Japan, he has a series of books detailing the construction, by hand, of a huge variety of patterns. He has a number of YouTube videos as well:
https://www.youtube.com/user/kskdesign1/videos
Here are a few of the Kumiko panels I've incorporated into recent work:
Attachment 466477Attachment 466478Attachment 466479
The jewelry box is a Matt Kenney design. The others are my own.
Mike