You can play CraftUnderWater by adding the server in the Minecraft launcher.
On Minecraft Bedrock Edition, open the Minecraft launcher or Minecraft app. Go to the “Servers” tab and press “Add Server.” Enter the CraftUnderWater IP Address 144.91.92.247in the “Server Address” and the CraftUnderWater port 19132 in the “Port.” Then press “Save” and start playing.