Oh, grechka! I might be wrong but I think it is indeed buckwheat, or at least a type of it. I've heard it's quite healthy, like a good source of fiber or something. I'm not entirely sure, but I guess it's good for you if you're looking for whole grains.
As for cooking, maybe try it like rice? I've seen some recipes where you use a 1:2 ratio of grain to water. You probably bring it to a boil first, and then I think you simmer it for a while, like 15 or 20 minutes? It's important to keep the lid on, I believe. And don't stir it too much or it gets sticky, I think. Then let it rest for a bit. My friend makes it sometimes, and it always turns out pretty good. It has a kinda nutty taste, if I remember correctly. I hope this helps a little, I'm not a cooking expert by any means!