Chop creamed coconut finely and then place in a food processor/blender with 300ml of the water.
Blend for about 5 minutes, add vanilla and salt whilst blending. Add the another 300ml of water gradually.
Meanwhile place a muslin cloth/thin tea towel in a mental sieve over a large bowl.
Stop food processor and pour liquid into the muslin cloth. Then you just wring out the milk through the cloth. If you are short for time just hook the muslin/coconut mixture up (door handles are good for this) and allow it to drip out or just wring it out tightly by hand.
Add the remaining water to the milk.
Place in a glass bottle and store in the fridge for 3-5 days.
Notes
Feel free to add more flavours like raw honey. Also you can make if you want it more creamy, just use more cream coconut, but coconut milk is not naturally very thick - that is why they add thickeners to shop bought stuff.