Grains are kefir colonies. Colonies of bacteria and yeast which form a gel that looks like cauliflower. Its actually a colony of microbes and the various products they produce.
Kefir is also available as powdered starter. This is a somewhat simplified form of kefir that is sprinked into the coconut water just like you would add probiotic powder.
The kefir starter powder I use is from a store called Body Ecology.
I am not sure what they mean by crystals. Maybe someone else on the board here is familiar with that.