Add the water and coconut sugar to a saucepan and bring to the boil.
Reduce the heat to low then add the ginger and simmer (uncovered) for 35-40 minutes. The volume of the liquid will have reduced and thicken somewhat (that's when you know it's ready).
Remove the saucepan from the heat then allow to cool at room temperature
Strain through a fine mesh strainer (save the ginger slices to use another time if you wish).
Transfer the liquid into a jar or container and refrigerate
Notes
It is normal for your ginger syrup to look dark because of your use of coconut sugar.
The consistency of the syrup is somewhere in between - not watery but not thick
If you want a very thick syrup then you will need to mix tbsp of tapioca starch with a tablespoon of water together and add during the simmering process.
Keep the syrup refrigerated. Be sure that any leftover syrup is kept refrigerated at all times. Don't store at room temperature, in direct sunlight or on your counter top.
Jazz things up. You can diversify your syrup by adding vanilla, spices i.e cardamom, nutmeg, cinnamon, cloves, allspice to yield a flavour of your choice.
Adding minced/grated ginger may result in shortening the lifespan of your syrup. Only do this if you intend to use immediately or within 1-2 days.
Grated/minced ginger combined with the slices will yield a more indepth flavour.
You can adjust the sugar to water ratio to suit your needs. 2:1 water if you want more sweetness or 2 parts water 1 part sugar for less sweetness. I keep it equal so have no first hand experience with toying with the ratio.