You can play A Towny 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 A Towny Server IP Address play.atownyserver.comin the “Server Address” and the A Towny Server port 19132 in the “Port.” Then press “Save” and start playing.