1 cup unsweetened shredded coconut
4 cups filtered water
a nut milk bag (paint strainer bag, clean kitchen towel, whatever works)
That is it! Obviously, you can add sweeteners (vanilla and some whole dates, for instance if you want a drinkable, cereal ready milk).
I then throw the cooled coconut and water mix in the Vitamix and ramp it up to ten then to high for a count of 60.
Dump the pulp back in the Vitamix. Add another cup of water and give it another run through and strain this. You'll wind up with very little pulp, maybe a 1/2 cup, once you've strained it well. I've dried the pulp at this stage and ground it into coconut flour, but I have yet to experiment with using it. You can always compost it.
I also make almond milk in much the same way (same proportions) and often make oat milk for baking that is lower in fat. With the oat milk, the water can be room temperature and I do a single run through and strain through a fine strainer. Trey the dog loves to eat the oat bran pulp on his food and seems to think it's a treat.