You can play Cats Little Server 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 Cats Little Server IP Address catslittleserver.serv.gsin the “Server Address” and the Cats Little Server port 19132 in the “Port.” Then press “Save” and start playing.