Take a saucepan and add the water and sugar to it. On the heat at medium dissolve the sugar in water properly and make little thick consistency of water
When the sugar dissolved in the water completely then off the heat and put it aside to cool down. at room temperature.
When sugar syrup cools down properly. Then Add the water and coconut milk to it at room temperature.
Mix these ingredients completely. Transfer the whole syrup to the bowl and put it in the refrigerator for 1 hour
If you have an ice maker then put the stuff in the ice cream maker for a further 1 hour to give it a proper shape
Then use the coconut shell to serve the coconut ice cream in shell.