What is the best way to sharpen Kamikoto Japanese cooking knoves?

Your best bet is to return those knives and get real Japanese knives. Kamikoto engages in fraudulent advertising (fake “sales” all the time) and generates fake reviews for itself while enticing buyers who don’t know about knives with fantastical writing. Their knives are relatively soft, which you almost never see in single-beveled knives. The try to draw attention away from the important specs of the knife and the steel used by doing stuff like saying “Honshu steel,” which tells you absolutely nothing of worth. Not to mention that they are terrible knives.
If you insist on keeping them, your best bet is to sharpen it like a traditional single-bevel knife. First, lay the bevel side flush against the stone and sharpen to the degree you like, moving up higher and higher grits, as you want. Make sure the bevel is always parallel to the stone’s surface. In a way, you are doing a polishing of the entire bevel, not focusing in particular on the very edge. When you are satisfied with that side, then lay the flat/hollow side flat against the stone and perform light finishing strokes trailing away from the edge. Single-bevels are actually pretty easy to sharpen when they are well-made because the knife itself guides you most of the way with straight lines that evenly contact a flat stone. Make sure the edge is deburred. Cork, leather, or denim are good common materials for this. You can strop if you want to further refine the finished edge. That’s all. You do not want to oversharpen the flat/hollow side because doing so will dramatically reduce the lifespan of your single-beveled knife and make sharpening it more difficult. Some people like a different process and will do things like put a microbevel on one or both sides but that’s just overly complicated to me and not necessary unless the edge is incurring microchipping at an abnormally high rate.

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