[Sycra] invented that method, so it’s not too well known, which is why few people talk about it. Even the [Japanese tutorial] you mentioned references [Sycra’s] [videos].
I did find [this blog post] with studies of figures made using the lightning bolt method, though.
There isn’t much to it, but you should have some understanding of anatomy to really get the most out of it; each of those zig-zagging lines fit pretty closely with the muscles and bones under the skin.
You can practice by finding and tracing the patterns over a photo like so:
(image from [SenshiStock]) then try doing it freehand.