You can play RiverStyx 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 RiverStyx IP Address 135.148.135.150in the “Server Address” and the RiverStyx port 19132 in the “Port.” Then press “Save” and start playing.